The new Playstation store might already be a few weeks old, but that doesn't mean Sony isn't finished working out the kinks and glitches in the store's updated design.
This purchasing glitch specifically targets the people who are trying to use the Playstation Plus extended free trial service. Usually this trial service is used to try out games before you buy them, but since the new PS store released they've been doing a whole lot more than that.
When you download one of these trials, the store will register it as you buying the actual full game. The game's price will vanish and it'll appear in your download history as being bought. While that might sound like a win win for you, you haven't actually bought the game. You'll still have a one hour limit to play. Here's where the annoying part comes in.
Once that hour is up you'll be asked to purchase the full game. But you can't purchase it because the store has registered you as already having bought it. If you use the store search engine to find the game you'll be able to see it's price, but you still can't buy it.
Instead the store will tell you the game isn't available for purchase and kick you back to the front page. There could be a way around this, but so far I haven't found it. I've been completely locked out from buying any game I downloaded a trial for.
So if you're currently looking to buy a game off the PSN, you probably shouldn't download that free trial. Posts on Cheapassgamer confirm this glitch is effecting multiple users.