Can I use drop-down field for Non-Profit DONATIONS instead of the free-form amount field?

I want to use the "donation" feature offered in conjunction with PayPal (as we are a non-profit), but would prefer to have a quantity drop down instead of a free-form amount field.  This is because we are having a student fundraiser and they receive one "point" for every $10 donation.  We are calling them sponsorships.  So we would like donors to choose from the drop down how many 10-dollar "sponsorships" they are purchasing.

It seems that I have the option of the drop-down pick list for products, and free-form field for donations, but I can't combine the two.  Please help, thank you!

In this case, you can use a normal Drop Down field in your form to enter the Drop Down quantities, and include a Form Calculation widget to perform the calculation:

And finally pass the total value to your payment field: http://www.jotform.com/help/275-How-to-pass-a-calculation-to-a-payment-field

See my example: https://form.jotform.com/60495317270960

You may clone my form to inspect it further: http://www.jotform.com/help/42-How-to-Clone-an-Existing-Form-from-a-URL

Let us know if you need more help.