I think a very good thing to do is bid auctions; when you have bid 10 times, you have earned 1 free spin to Build a PSA. Mostly, it will take 8-10 spins to complete a PSA, but if you are bidding anyway... Might as well go for the extra bonus of gaining more PSAs while you try to win the auction.
You will also gain at least 5 MRPs/bid, and there are many things you can buy in TripleClicks for MRPs, including TCredits!
