The price doesn't sound outrageous, but I'd be more curious about what gun the scope is intended for, or for what purpose.
I've got the 3-9x40 ProStaff, & I'm pleased with it for the $150 I paid. However, it's certainly not among my brightest scopes, and my hunch is that putting a 50mm lens in that scope for $189 means that the glass won't be of the highest quality. In other words, I'm not convinced you'll be getting much for your money.
Just my $.02.
FC