i was reading at /warp bank i could buy a vault and put brewing stand enchantment tables culdrens and so and so how do i buy 1 and who do i ask about it and how much do they cost ? wouldnt mind a piecefull place to enchant brew and store stuff at how do i buy one?

you do /warp vault and it shows you all the vaults you can buy. If you would like an example of the vaults, just right click the sign. It has the prices on them, it also shows how to buy them.

o so its robotic i dont need help from a admin in order to buy 1? sweet does it save your old or should i store my stuff from my old before i buy a new 1 so i dont lose it?

Yes, you keep your old one.