No a half gram wouldnt, it doesnt matter whether your a 1st timer or not, it all depends on the quality of the product, you could kill a half gram in 1 line if you wanted to ,but to stay high for a couple hours, i would say get at least 2 grams , do a line every 20min-30min, otherwise just get a whole 8 ball, and get some beer, that way when your done with coke you will have a nice alcohol buzz, but have either some weed, or some benzo's on hand to help witht he comedown , cuz once your out of coke all you will want is more.. and boy does that feelin suck.. Me i dont like coke, high is not that great , niiice but over priced...