Vendor-different Linden choices on one item?

We are thinking of adding Gift Certificates at our store but I haven't found a vendor script where a customer could click on one certificate and make a choice of what amount they would like in the pie. Does anyone know if there is such a script available?
Thank you in advance

Almost any multi-item vendor should be able to handle changing price values.

If you're writing your own script, it's a matter of calling llSetPayPrice() to change the price in the requester. Don't forget that your money() event must always check that the correct amount was paid.

I suppose what Belle wants is that the vendor "loads" a specific item with a certain value that depends on the amount of money the purchaser paid in.

Unfortunately there is no way to modify an object before you give it out.
Also, having the object contact a server to obtain its "value" once it is rezzes may not turn out to be an easy task to do.

What you should therefore do is have "certificates" of different value already prepared in the vendor and have the vendor hand out the matching certificate on purchase.

That should not be all too hard to do and would be the easiest (if not cheapest) way to do such a thing.