Really depends on your area
All the stores that are local to me sell silvers (of any size) in the $90 range. In San Francisco, I can get larger sized silvers for $20 with no tax.
Blacks usually go for $250+ (again, any size)...and you would be lucky to find one. Even down in the city they are hard to come by.
The only place I have seen Jars for sale had them going for $40-50...and they were small.
If your local prices have gone up, I would blame it on the gas prices being so high. Transportation of fish to pet stores would've gone up, thus raising the selling price. I know the "big box" stores have raised prices because of this.