Actually, Thomann UK is giving me a UK price for the Quad VCA of UKP 170.43, with VAT included. The same thing in EUR is 199. And when you switch those to $, you get 224.19 and 225.05 respectively. But if I use Thomann USA, then the same module is $188. So what gives?
Simple: there are going to be taxes and tariffs that vary from place to place. Intellijel, for example, is a Canadian firm. So let's look at Moog Audio (based in Montreal) where we find that module at CDN$ 250, which comes out to be $186.75. So...that's different, too. Therefore, it should be considerably more in the USA, right? Well...no, as Perfect Circuit has 'em at $189.
Sooooo...it's not merely the taxes and tariffs. In some cases, it comes down to an agreed-upon price for a module between manufacturers and retailers, too. Perfect Circuit is nowhere as huge as Sweetwater...but there, too, we find the Quad VCA in question at the same $189. And when you look further, you'll tend to see the same "street" prices from continent to continent. Looking at one place in Asia that has serious tariffs, we find that Clock Face (Tokyo) has that very same module for JPY 22,900, which comes out to $207.02.
This gets screwy all over the place. If you think you're getting overcharged for new Intellijel stuff, have a look at what new Doepfer gear costs at Schneidersladen...and then check the same things at Perfect Circuit or Analogue Haven. This problem is just an endemic effect of having manufacturers all over the planet.