I had 10k+ IP. When I tried to purchase a run page for 6300, I got a message "Not enough RP/IP". I was buying other things at the time, so it's possible I didn't have enough. I tried multiple times and got the same error each time. So it looks like 2 possible cases:
1. Client gave an errant message about not having enough IP.
2. Client displays the incorrect of IP for my account.
I've only had this buy happen a couple other times on the PBE (never live). Will post again if it happens again.