I suspect that giving users a blank field to fill out may result in increased payment amounts. If a user tries to checkout with no amount, maybe reload the page

I suspect that giving users a blank field to fill out may result in increased payment amounts. If a user tries to checkout with no amount, maybe reload the page with a high amount pre-filled for them, like $25, that they can then reduce. But there's just no way, psychologically, I'm going to move that slider to the right. (If many have, I'd be interested to hear that.)