Steam Payment Problem?

Not at the moment, but I've had this error before. If you have tried both the client and the browser and they both give you this error, just wait it out for a few hours. It's usually fine by then, at least for me.

I have that problem sometimes too. Try making your purchase using a different browser or going in Incognito mode in Chrome. Works for me that way.

I restart my client or the browser and it seems to help most of the time