Paint is best when purchased from companies making the paint for your application.
If you live like you paint, and are a crust of day old pizza use hardware store shit like me.
If you've got style and like having your shit come off crisp, forget about the fancy paint and concentrate on your letters.
Nothing worse than a bubble gum pink toxic ooze green and Barney purple toy assed happy graff.
Experiment with better paint and applicable caps with tags, develops them and learn the art of flairs.
Groom yourself as a bomber first, graffiti guy second.
Bombers don't even have to be graffiti guys and I still look and respect there shit in full and never giving an actual glance at colourful, overly clean for the level of letter skill, soft assed under a bridge in the middle of a forest irrelevant burners.
If I could give one piece of advice to a young writer, that I can tell by means of assessing other elements of his make up and is in turn worthy of such invaluable guidance, I'd say do grimes graffiti, and do it with an attitude that best suits your character.
But even if your a chill kid from the burbs, start with raw shit, and develop other traits as suited to what your initial interests in the culture that drew you in.
But always, always, always put raw, real, letters over all else no matter how jaded you may be in this prepackaged global FONT we call graffiti.