Where can I find retro (early 90's style) video game sound effects.  I used soundsnap, but the sound effects are too realistic for my retro-style game.  Plus, it isn't free anymore (http://forums.xna.com/forums/t/22071.aspx).  I want sound effects that are actually more realistic than Sega Gensis / Super Nintendo, but not so realistic that they sound completely out of place.  I almost need a mix.  For example, to replicate a huge explosion, I want a sound effect that can be played over and over, instance after instance of itself, as opposed to one large realistic sounding explosion sound effect.  And if I want a smaller explosion, I just play less instances of the same sound.  I hope you follow.  It has that retro feel.  Almost no sound effects off soundsnap work for this.  They are too realistic or have too much reverb and echos.  When I put sounds like this in my game, they sound horrible.  It's difficult to describe exactly what I am looking for, but if you can give me any leads, that would be great!

Design the sound yourself. Use a tool like Audacity, WavePad or Wavosaur to create sounds out of bleeps and noise, that you run through envelopes and filters of various kinds.
The "retro" sound often comes from using square waves for tones, and quantizing the sounds to 8 bits (or even less, like 6 or 4 bits) and using a low sampling rate (like 11 kHz or 16 kHz) with nearest-sample interpolation, to add a lot of aliasing noise.

There's also this free little tool I've been using called sfxr. Great for making quick sound effects, but it might not meet your needs because it might fall into the "too retro" category.