What to Spend $$$ On?

If you don't mind gambling, spend money on the game. Otherwise, just stay free-to-play. Honestly, I've read nothing but bad things about most of the kits they offer for players to buy. Especially the big character shard packs like Gifafi already mentioned. The chance of actually getting your money's worth is slim to none. Unless a pack is guaranteed to pay out a set number of shards or crystals, I'd definitely stay away from it. I haven't spent any money because of the things I've mentioned here.