Only way to tell if it's been laced or sprayed is if it smells funny. I mean, don't worry if it smells a little different than normal but you should be able to tell if it has a Raid scent or something like that lol. PCP supposedly makes a huge difference in the smell too, and if it was laced with anything else more expensive it wouldn't be 80 for a quarter because that wouldn't make the dealer any money. My call is that it's probably good weed, not purple haze though. He's probably just applying the name to make it sound better, but it's probably just good, unlaced weed so go for it.