I'm right in the middle of buyin loads of cheap stuff in a user shop for the recycle beast and all of a sudden I cannot buy anymore "purchase failed" - I also tried another shop. After waiting for a few minutes I tried again and got 4 more items, now I a m back to not being able to buy anything and "purchase failed" notice.

Just me or others, too?

I'm buying things just fine. Do you have enough sP on hand? :)

Sometimes if you're not quick enough someone'll buy the item before you, and then when you try to click on it it'll say the purchase failed because it's not there anymore. Ran into that problem frequently when trying to get certain good deals (ie a 500 sP book when the rest were over 30000 sP more) during the book drive. Odds are if you're clicking the first shop all the time, someone's just getting to it before you are.