Welcome, mate. Sounds like you got a great tank.
$80 would be ok from an LFS. From a private owner? May be a bit steep. It all depends on whether he wants to unload the fish or it is you who really want it. If the former, $0-$50 would be fine. If the latter, $100 is fine. But as stated above, one can get a 5" baby for $20 and, if all is done right, he will be 15" in 5-10 months.
$80 would be ok from an LFS. From a private owner? May be a bit steep. It all depends on whether he wants to unload the fish or it is you who really want it. If the former, $0-$50 would be fine. If the latter, $100 is fine. But as stated above, one can get a 5" baby for $20 and, if all is done right, he will be 15" in 5-10 months.