Is the discussion about numbers based on the long term or the short term? Short term you could put 50+ in a 265 gallon. For the long haul, I'd suspect a dozen would be a good number. They get to be thick, 12"+ fish and take up a lot of space.
As for pricing, @1"-2", you'd be able to find the cheaper ones for $5ea and the most expensive would probably run up to $30ea. Larger fish start to cost quite a bit more unless you find someone in need of selling quickly. As mentioned above, they grow decently quick for a bit, then slow down.
Regarding barring, incomplete or improper bars are a defect. If you'll never be breeding them, maybe it's not a big deal, but I wouldn't pay the going rate for substandard fish. You may also have trouble selling them later if the markings are poor. Also take a few moments to lookup what "mooning" is with regards to frontosa.
Unless you've fallen in love with them already, I'd suggest trying to watch someone else's adult colony for a while before getting any. They aren't like haps/peacocks. They'll all be the same colors. They may "think" a bit more and show more 1-on-1 interaction with you, but they aren't always showy/flashy/action-oriented and become more cautious as they grow older IMO.
