I'm trying to make a donation form

instead of little radio circles, i'd like to give them big buttons with amounts on them to choose from.

is this possible?

Id be using stripe integration

If you are using a Classic Form layout, the size of the radio buttons can be increased with CSS. 

You can add this CSS code to the form:

.form-product-item-detail,.form-radio{

    width: 20px;

    height: 20px;

}

How to Inject Custom CSS Codes