I think HODL strategy has always been best when trading bitcoin but I know nothing about trading anything.
Dont make up an opinion when you dont know about it buddy.
Good luck in running that business and while you are at it I guess you are looking to hold off some profit in bitcoin. Well the thing here is that you should use whatever exchange you feel comfortable with but directly buying bitcoin with credit card is an issue. Like Le suggested, Changelly allows that but they are again having some accusations in this forum for forced KYC, but you might them useful.
If you live near a bitcoin ATM then you are very lucky, specially if you are in North America, they are abundant there as far as I know.