Update (11:30 am PT): the purchase was successful and the issue appears to be resolved. We will continue to monitor the situation closely.

Original post Steam's payment system appears to have crashed, less than an hour before the Halloween sale ends. The issue was first reported on Reddit, after which I went to Steam and attempted to purchase a 59p platformer. I then tried to buy the 59p platformer on Steam and the transaction hung for a while: "There seems to be an error initializing or updating the transaction. Please wait a while and try again or contact support."

Obviously, the timing is bad; we have asked Valve for comment and will update as soon as we have more details. Even virtual bank accounts seem to fill up at times.