How much does their clog blaster cost?

Depends where the plug is. If it's at the sink. Try taking the stopper out to clean it out. Depends where the plug is. I use a clean out coil, that cost about $10 . It works if you can get to the plug

I prefer mainline cleaner and that's around$20, but works better than anything else I've tried.

If you are talking about hair clog blaster it is $6.99 but $1.99 online sale price!