The Korg MS-20 mini sells for $450, the Moog Mother-32 sells for $600, and the new Behringer Neutron will sell for $300 when it comes out. Semi modular synths are pretty cheap these days even though they aren't quite as cheap or popular as non modular synths like the Arturia Microbrute or the Korg Monologue.
A basic modular system with all the basic oscillators and filters you'd find in a standard VST plugin set will cost roughly 5 thousand if not more. It's a bit expensive really, but I suppose that's the cost of analog in a digital world. It might just be me and my reluctance to spend money but it seems like prices would be dropping for equipment if it was making as big of a comeback as it is, but prices seem to be relatively stable, sometimes more expensive as new small scale manufacturers come out with modules.