Where are you in NY?
The best price on GBRs would be at Fishtown $6, call them to see if they have them.
If they are small with high color, I would pass!
Not easy to find good GBRs.
They had nice ones on 38th st NYC, but at $12 each.
Animal Pantry has them sometimes, but call they didn't get them for a while, and they usually get high fin, not standard.
Nothern Aquirium had them at like $11, they looked good.
Pacific mostly has the balloons.
I have seen Otos at Petland, but I think of Petland as Petco, don't know much about fish quality.
I had good luck with getting Otos and Rams from Coral on Roosevelt Ave. in Elmhurst.
The list of stores/locations is in one of the posts here if you look.
Make sure the Otos you get are nice and fat and keep feeding them with greens.
Re: GBRs if you watch the tank for 10 min you can usually figure out which rams are male, if they are small and no color. they are the ones that are more aggressive.