I don't suggest you making booters if you have not the scope to earn some money. Also, to make an online booter via web you should make it doing xr-shell based attacks, which isn't a method often used. The other method to do it is buying spoofed servers, then code some C/C++ scripts able to emulate DoS/DDoS attacks.
My friend is selling a stressing service which uses the second method I wrote you. But you should respect a predetermined ethics, and so you should stress your only infrastructures, in any case no one would be responsable of your attacks. PM me if you are interested.