I've brewed a Donate by Card function for my webpage. It's working in test mode (with dummy card numbers). Now I am looking for somebody who could make a real donation (only a small $1 amount for testing). If somebody could help out: Please PM me (the Donate by Card page is already online on problemkaputt.de (and uses secure https for the payment stuff), but, as it's still untested, there's no public link to that page yet). Some feedback would be also nice (does the payment page work with your browser, does it appear trustworthy & user friendly, and what kind of info do you receive in your credit card statements).
I would be really glad if somebody could help on testing! Living in germany, I don't have a credit card myself, and that stuff isn't too popular over here - but I guess it's more popular elsewhere, and the transaction fees are ways lower than overseas bank transfers, so the credit card stuff would allow me to receive donations from outside of europe.
EDIT: Already found three testers. Thanks!
Testing is under way, I hope it'll work and I won't get told that php user interface is total crap ; ) unless it is crap - then tell me!
Oh, and I got asked if donations could be bundled with Feature Requests... the answer would be yes/no/maybe/sometimes. Normally I am hopping between no$sns/no$psx/no$gba/etc working on new ideas & todo-list items depending on the mood of the day. And, well, unfortunately I am working best when doing stuff "for fun" rather than "for money", and working at my own speed without deadlines and without responsibilities.
Anyways, of course, everybody can always send requests/suggestions (with or without donating anything), and then, well I can promise that the idea "might get buried on a todo list", or maybe I'll get it implemented someday. Another option would be offering a donation if I implement on a specific feature... normally I would probably say "leave me alone with your money, I am busy doing unpaid work that is ways more interesting", or if I am not busy & I like the idea then I might feel motivated doing the work - and even getting money for it! I am afraid it isn't too praticable for bigger projects, $500 for 2 weeks work would sound inviting, but I guess that few people would ever offer that much (unless it's done via crowdfunding, but collecting money in advance is too much hazzle, and if it's working then I would feel like having trapped myself, with dozens of people excepting me to do the work, not to mention that it would be shabby to finish the work without offering t-shirts and coffee cups to the supporters).
PHP offers many ways to shoot yourself in the foot. Since this is probably your first PHP project, I'd highly recommend you to ask someone who knows PHP well to audit your code.
You might also take a brief look at security standards for payments och security standards such as PCI-DSS. For example, it might be good to keep a transaction log. But only store it for as long as you need it. But you're not allowed to store the CVV code, and you should make the card number identifiable but unusable, typically by storing only the last 4 digits.