If you look at some of the level 4 synthesis items you will see that some recipes costs 16k. That said, obviously 16k is not enough to buy all the items in the game. Try somewhere 150k+ to get all the items.
In terms of play through, it will take you 4 playthroughs (give ups) assuming you don't cheat and do all the side-bosses and quests, or 5 if you are not as thorough.