That is a strange answer. I'm sure they are not the most popular fish in the hobby, not even the most popular cichlid. $2 a fish is not a great deal on those either. I'm guessing they sell for between 20-40 each. I'd like some taiwan bee shrimp for $5 a pop but that doesn't mean it's going to happen.
Some fish store's are not worth dealing with and will give you almost nothing in store credit and only take super high quality adult fish, in very small quantities. They should be giving you at least 40% of what they sell the fish for in store credit, or 25% in cash. Good stores give you 50% or more in credit.
A store isnt going to give you 40% of what they will make on a fish, they need enough to pay cost of bringing in the other fish in the store, electric and water bills and taxes, if your lucky you would get 25% of the sale of the fish, and since Blues go for around 25-30 dollars you should be getting around 6.50 per fish, 2 is low for adults, Unless your selling Juvies or fry try and get a better selling price, Also ive never seen a store give 50% in credit
Ask for like 5 dollars a fish if the owner could do that, thats probably a fair starting price, or if you start lower and bring in High quality fish you might start to get more Money or credit because you bring in High quality fish