**Boris**Yes, this is possible, but we'll have to collect the amount your users wish to donate through another form field. Please see the following demo form to see if this is what you are looking for:

https://form.jotformpro.com/form/63366795402967

Step 1. What I did to set it up is I first added a

**Number field**to the form, made this field**required**, and set its**default value**to zero:Step 2. I added a

**Form Calculation**widget to the form, and set it as**hidden**:This Form Calculation should be set to simply get the value of the number field we created in Step 1:

Step 3. Run the payment wizard:

Edit each of the two subscriptions:

And set them to

**Get Price From**the calculation field in step 2:Step 4: Finally, we can create a condition to hide the Submit button / prevent form submission when a value in our Number field is too low. The following guide shows how to use show/hide conditions:

https://www.jotform.com/help/316-How-to-Show-or-Hide-Fields-Base-on-User-s-Answer

For practical reasons, I've chosen to "Show Submit button IF number field is greater than zero":

Please try it out, and let us know whether this works to your satisfaction. Thank you!