no problem answering from my own experience. you already know that you're not ready, so i think its a question posed with some sort of, ummm learning intent, i guess.
I was fortunate enough to have friends with connections. I was very wary of the local "sources" I was intoduced to through fellow gym members.....so i just went with what some of my experienced buddies suggested when it came to who to buy from. of course i took the time to research AAS and known counterfits/fakes and was very wary in that regard.
those days are over though. homebrewing is the best way to go IMO. cuts out the middle man, and you know you are getting quality products, you know exactly whats in it, what dose, what volume is in the vials, you are sure of its sterility, and you don't get fucked over paying ridiculously marked up street prices. thats all assuming that your powder source is top notch and your brewing techniques are sound.