Hey Nemo,
The SH-101 is a very basic monophonic synth with only one osc and one lfo, so pretty much any subtractive VST will have it's features. Where the SH-101 shines is that it's, of course, analogue... so it can do some amazing bass without the sound breaking down and getting muddy... which is a problem for digital synths. With soundcards capable of higher sample rates this becomes less of a problem, but they still are just a sample of the real thing.
As far as a cheap (or free) VSTs that can do killer bass, I'm a big fan of Bazzoid. I've also heard great things about Synth1 and Tau.
But, unless you have a meaty soundcard, you're not going to get the clean ripping bass that only analogue offers.