ya man, just eat eat eat. Thats the best way. Don't go wasting hundreds of dollars on supplements that don't work. If you're gonna buy something, buy protein. Either that or spend it on food.
I see many of my friends pissing there money away on GNC supplements, most of which don't do anything but take up space on there closet shelf.
EAT, EAT, EAT. Thats the best way to put on some muscle.
Oh ya, you gotta lift too, that helps sometimes.