Purchase trick, back out to other tricks menu, go back into the slot and its empty, and i spend like 5k on the same trick.

I know what you mean. Sorry to hear you spent the money and can't use the trick. I am having similar issues. I haven't bought any tricks lately, but have been re-arranging my flip trick combos in the menu and when I finish my setup, hit accept, back out to the skater select screen, continue onto the map I want to play, the combos I selected are not registering. So I went back to the flip trick menu and the ones I adjusted said "empty". I filled them back in and still didn't work. Then I cleared all the flip trick slots, started over and put them back in, went to Venice beach and guess what......i HAVE NO, ZERO, ZILCH flip tricks!!! I am going to try a restart of the game, then the xbox, and see if I can find a resolution to the issue.

I was having the same problem when switching around my flip trick combinations. When I saved them and went back to play, they were not working. So I started fresh by clearing all the slots for my flip tricks and re-entered them hoping that would be the best way to keep the tricks in restoration. To no avail, it did not work...when I played, I had no flip tricks at all. SO I went back to the store and sure enough, all the flip tricks said "empty."

I tired it a few more times and nothing worked. SO I exited the game, went to my Xbox home page, system settings, storage device, and hit "Y" to clear the cache of the hard drive. Then went back to the game and loaded up Emily Westlund, went to her tricks store, to the flip tricks...and yep....still all empty. So I input them back in, hit "B" to exit, went to free skate on Venice, and it seems to work now. I have yet to go tinkering again with the grab tricks, or specials, but after clearing the cache and restarting the game, and inputting the flip trick combos again, it has seemed to work. Maybe try clearing the cache on your storage device where you save all your games.