Hello House pls i want to ask if anybody knows where i can buy bitcoin cheap and sell at a higher price at the same time or within same day
I think that for this you will most likley need to investigate on your own. To look for available exchanges and to calculate their fees and see if it could make you some profit. I assume that this would work, although I haven't tried to do this in the past. You will want some exchange that supports SegWit since you want bitcoin network to process your transaction fast since price can change quickly as well.
Maybe you could try to get verified on some exchanges and to build up a profile on localbitcoins or paxful where you could sell for a bit higher price. But do note that in some countries (if not in all) you will need an permit to do this as you are exchanging money with other people in case of localbitcoins.