Trial and regular products in the same cart

Use ConvertPlus to sell a trial product and one or more regular products in a single checkout. The shopper pays for the regular products immediately, while the trial product starts at the trial price, free or reduced, and converts to full price when the trial ends.

Previously, a ConvertPlus link supported either trial or regular products, but not both. See ConvertPlus trials flow for links with a single trial product.

Requirements and limitations

Rule	Details
Products	Catalog products only. Dynamic products, created on the fly with a custom name and price, are not supported together with a trial.
Purchase type	New acquisitions only.
Number of products	Maximum one trial product and any number of regular products. A link with two trial products cannot be created.
Custom price	Not supported anywhere in a cart that contains a trial, not even on a different product than the trial one.
Currency	The whole cart uses a single currency, set with the currency parameter.
Payment methods	Credit/debit cards, PayPal, and Direct Debit. These are the same methods available for trial-only carts. The restriction applies to the whole cart, not only to the trial product.
Checkout template	Hosted ConvertPlus templates only. Use the classic ConvertPlus checkout link (checkout/buy).
Signature	Required. See Sign the link.

Build the link

Pass all products in the prod parameter, separated by a semicolon (;). Add tprices and tperiod to make the last product into a trial.

Parameter	Description
prod	Product codes separated by ;. A cart can contain any number of products. For example, prod=PRODUCT_A;PRODUCT_B.
qty	Quantity of each product, separated by ; in the same order as prod. For example, qty=1;1. The trial product's quantity is limited to 1.
opt	Optional. Pricing options, such as color or plan, for each product in the same order as prod. Not applicable to the trial product.
price	Custom price. Not supported in a cart that contains a trial product.
currency	The cart currency. Required when you set tprices.
tprices	The trial price, per currency. For example, USD:0,EUR:0 for a free trial, or USD:10,EUR:9 for a paid trial.
tperiod	The trial length in days, from 7 to 99999999. For example, 7, 30, or 57.
signature	The link signature. Required, see Sign the link.

tprices and tperiod apply to the last product in the prod list. Every other product stays a regular product at its catalog price. The order of products matters: the trial product is always the last one listed.

qty, opt, and price are positional: each value matches the product at the same position in prod. Adding a trial does not change this.

Use the right separator

Separate products with a semicolon (;), not a comma. With a comma, the whole string is read as one invalid product code instead of several products.

	Link fragment
Correct	prod=PRODUCT_A;PRODUCT_B&qty=1;1
Wrong	prod=PRODUCT_A,PRODUCT_B&qty=1,1

Example

This link sells PRODUCT_A as a regular product and PRODUCT_B with a 30-day free trial:

https://store.checkout.com/checkout/buy?merchant=MERCHANT_CODE&tpl=default&prod=PRODUCT_A;PRODUCT_B&qty=1;1&currency=USD&tprices=USD:0&tperiod=30&signature=SIGNATURE

At checkout, the shopper pays the price of PRODUCT_A today. PRODUCT_B costs 0.00 today and is charged at its catalog price when the 30-day trial ends.

How the trial product is identified

A product is the trial product if it has its own tprices or tperiod value. Having both is not required to identify it, but tperiod is mandatory for the trial product.

The trial is matched to the position among the actual products in the list. A trailing ; or an empty entry does not shift the trial to another product. If your link generator adds one tprices or tperiod entry per product, leaving the entries of regular products empty, the link still works.

Pricing options

Pricing options (opt) work the same way as in new-acquisition and upgrade links. They do not apply to the trial product. If a value falls on the trial product's position, the last one in the list, it is discarded and no error is returned.

Coupons

Standard coupon rules apply:

• Discounts on regular products follow the promotion settings in the Control Panel.
• Discounts on the trial product apply only after the trial converts to a regular product.

Sign the link

A signature is always required for links with a trial, because the link always includes prod, currency, tprices, and tperiod. There is no merchant setting to turn this off for trial links. Generate the signature the same way as for other ConvertPlus buy links.

If the signature is missing or wrong, you will not get a "signature invalid" error. The signed parameters, including prod, are silently removed from the request, and checkout fails with a generic error such as "Invalid parameter". If a link fails this way, check the signature first.

What the shopper sees

Cart

Mixed cart with a free trial and a regular product, with automatic renewal:

Mixed cart with a paid trial and a regular product, with manual renewal:

• Trial badge. The trial period is shown as a rounded green badge next to the product name. A free trial reads "7-day free trial" and a paid trial reads "7-day trial".
• Price column. Shows the amount due now for each product: 0.00 or the trial price for the trial product.
• Trial terms. A line under the product name explains what happens next. For example, Trial ends: Sep 29, 2026, then $14.28/month (incl. VAT). The text depends on the subscription type and renewal settings. See Renewal messages.
• Totals. The block is labeled Total due today and shows only the amount charged immediately, with a VAT breakdown line.
• Call to action. The button is the same as on a regular checkout, for example Place order or Continue to review, depending on the order flow.

Change the cart

Products that are locked, such as the trial product, cannot be changed in the cart, with one exception:

• The shopper can remove the trial product using the delete icon when the cart has other products. This lets them keep the regular products and skip the trial.
• If the trial is the only product in the cart, it cannot be removed.
• The quantity of the trial product cannot be changed or replaced.

After the purchase

• Regular products are charged immediately. The trial product starts at the trial price, 0.00 or reduced, and moves to full price automatically after the trial period. The checkout shows a single combined total, not one per product.
• The trial product converts to a paid product automatically/manually when the trial ends. The shopper can opt out of the automatic conversion from myAccount. Both behaviors are the same as for trial-only orders.
• Trial and regular products are independent after purchase. Each has its own subscription and renewal cycle, with no shared billing date, even though they were bought in the same cart. Cancelling or refunding one does not affect the billing or refund window of the other.

Troubleshooting

Issue	Cause
Checkout fails with "Invalid parameter"	The signature is missing or wrong, so prod was removed from the request. Regenerate the signature. Also check that products are separated by ; and not ,.
Error "Trial products can be only 1."	The link sets a trial for more than one product. Only one trial product is allowed.
Error "Trial products cannot be combined with custom priced products."	The cart has a trial and any product with a custom price, even a different one. Remove price and use catalog prices.
A regular product does not get the pricing option I set	The option was placed on the trial product's position and was discarded. Check the order of values in opt.
The wrong product has the trial	tprices and tperiod apply to the last product in prod. Reorder the list.
Some payment methods are missing	Carts with a trial only accept credit/debit cards, PayPal, and Direct Debit.

Related articles

ConvertPlus trials flow