Yeah, I'd avoid OldModelKits.com, generally, unless that was the absolute only place to find the kit you want. It's really more for kit collectors than modelers, the guys who want an original issue of a Monogram F4F in the box from 1958, unopened, with no thought of building it, just displaying it.
I mean, forty-two bucks for the old Monogram Me-109E kit? Are you kidding me? If you want to collect the kit, go for it, spend what you want. But if you want to build it, you can find it for five bucks plus shipping. Hell, you might find someone in a club or at a show who'll give it away.
And there are plenty of places to look, if you have a build in mind and the kit is rare. I'd exhaust all other possible sources before I'd pay kit collector prices for a kit I'm going to build.