Please re-frame your sentences. You want to buy whole bitcoin? LOL!

I think you are asking to buy 1BTC right? If so then it will be your decision. Probably now is the best time to buy 1BTC because price will rise two folds after next halving begins from June or July probably.

Do not wait for price to go down to $350 because Bitcoin is now stable at $400~ and it is not going down as I am noticing everyday. Nor it will either.