Coral prices

Hey guys I'm about to purchase some frogspawn & hammer coral (probably zoa too) from someone off craigslist and he's selling the hammer and frogsspawn coral for $5 for a head! Now I know that's a good price but how much normally would a vendor sale on of those neon green heads for?

Also anything to watch out for specifically with these guys? They have long sweeper tentacles so keep them spaced from other corals. Fragging info?