Adding options in my products

We're offering a mail free t-shirts to registrants for our virtual charity run. I've got my form set up with PayPal and that is working. However, setting it up as a product seems unnecessary, and the display is all squished.

This is my first form with this requirement, and I cannot figure out how to get what I need. I've experimented with other forms I've found but cannot wrap my head around how to do this. All I really want are these two things:

1) Ask if they want the t-shirt : Yes or No

2) Allow them to choose how many of which sizes: 0 XS, 1 S, 2 M, etc

This form is doing what I want, but I have not been able to set that one up with PayPal : http://awcthailand.org/virtual_test

You can set a condition wherein the payment field will only appear if the user chooses "Yes" in the question "Want T-shirt?". Please refer to this guide: How-to-Show-or-Hide-Fields-Base-on-User-s-Answer

I have checked your form and it seems that you already fixed this problem. You have 2 products, one is for the registration and the other is for the t-shirt. You were able to set options as well for the t-shirt. You might want to check this guide: How-to-Add-Options-to-Payment-Forms

If there are any problems, let us know. Thank you.

Thanks for checking my form. I see I was not clear. I do not want to have the T-shirt options in the payment field. How do I set the quantity and sizes in other checkbox/radio/dropdown fields? I need to offer multiple quantities of each size.

I think this can be done by following the guide shared by my colleague above, here is the guide as well: How-to-Add-Options-to-Payment-Forms

If you would need a different functionality, for example, allow your users to select more than one option for the same product, then it would require to use normal fields instead, radio buttons, check boxes, drop downs and then use calculations to get the total, this guide will help you with calculations: How-to-Perform-Calculation-in-the-Form

Then you will need to pass the calculated value to the payment field, this guide will help you with that: How-to-pass-a-calculation-to-a-payment-field

Maybe you can share us a bit more about what you're looking for, if possible, share us how the payment and products should work, we will be glad to help you. 

Thank you, Kevin_G. The form was revised based on the organiser's need, so I'm all set. You gave great advice!

Glad to hear that your form is all set now. If you need any help, let us know. Thank you.