It depends where you go here, Oscars are not like buying a package of cigarettes that cost the same every where, a fish store can charge what they like, some shops here are more expensive than others so in one store you can get a small three-inch Oscar for £4.95, whereas somewhere else it may cost you £6.00.
When I bought my Jurupari nearly 3 years ago, they cost me £7.95 each, I think there were 2 inches. Another shop 10 miles away were selling exactly the same sort at exactly the same size for £13.