I wanted to set up a single page where our members could pay for one or more club memberships.  I added each club's name, followed by a short introduction text, and then a donation part.  I was able to bring it down to one line (amount), and a "Continue" button.  The amount is preset, and the "other" option is off, so there's only one possible choice.  To start, I have two donation parts on one page.  When I use the page, however, the second donation part gives me an error whenever I try to make the donation: