Ideas on Setting up Customer-Specified Pricing?

[Guest]

I'm trying to set up a gift certificate product that a customer can set to any value they want (well, any value above $20, but that's the easy part). I've seen some suggestions out there, like having a base price and then a drop-down with other amounts to add to that price, but I'd really prefer to simply have a text box that the user can enter an amount into. Has anyone done anything like this? As it stands, my store just has a bunch of different denominations set up as separate products, but I'd love to make it more dynamic.

 

Thanks in advance!

 

Aaron