I've bought off CL a lot and never been scammed. Probably 15 for 15 over 3 years, almost all concert tix (a couple baseball games, one hockey). Hell, I just bought one 4 days ago. Make sure you get a phone number, just in case it's a scam. Most scammers aren't going to give out their phone number.
Most risky was 2X$125 printed pass that I had to drive an hour to get (paid $150). It was legit though, amazing seats, guy had a last minute emergency and couldn't go. My friend and I had a great time.
In your case, $25 for some little unknown band is probably safe. Most scammers aren't going to rip off someone for $25 (at least not around here). Maybe in Detroit though.