I can use FL Studio on any crap-tastic laptop I have
You'd have to dedicate this PC to gaming if you want to build one.
I recommend you look at some local stores and comparing prices before looking online and in fact weigh your options and keep it open (Don't rely on one brand because the price is just going to get higher and higher)
But don't go cheap with Power Supply Units, pick something like Corsair otherwise it'll definitly be Faulty or last less (if you're going for a gaming rig I recommend 500-700 Watts or so).
Also what's your budget going to be for it ($$$ Maximum), how much money can you save and how are you going to maintain the PC overtime.
And also think things through before making a final decision.
Well I know it sounds like a lot of work but building a PC you want to get the best Performance per dollar and have a proper knowledge-base before starting. Do all of this and I assure you, you'll have a PC you'll never forget