ilovefuzz.com

Digital or Analog. budget is under 500.

i use an m-audio keystation 61 es and an alesis lpd 8 with my macbook running lennar digital's sylenth1. sylenth1 is available as vst and au depending on your os. i love it. i have lots of other softsynths but haven't used a single one since i got sylenth other than NI massive which is nowhere near as easy to figure out. not sure if this helps you at all but its definitely under your budget! good luck!

Korg Monotron, $70 I think.

If you have a low budget some VST synths and a MIDI keyboard is the way to go. If that doesn't appeal to you, look for old stuff on ebay. Nearly every synth ever is considered "vintage" now so finding old ones cheap isn't all that easy either. Outside of that I recommend a DSI Mopho. It's monophonic, and you'll need a MIDI keyboard to control it, but it sounds great.

http://www.musiciansfriend.com/keyboards-midi/dave-smith-instruments-mopho--monophonic-desktop-analog-synthesizer/703408000000000?src=3WFRWXX&ZYXSEM=0&CAWELAID=242525196

The Moog Animoog iOS app just got ported to iPhone4 and the current iPod Touch, $0.99 introductory price. If I had an appropriate device, I'd be all over that.

MicroKORG
Novation Xiosynth

http://www.atomosynth.com/

Their Krakken has been on my mind for years...

Don't get a xio, they fall apart after about a week.

Mine did just fine until I sold it

Bellyheart wrote:http://www.atomosynth.com/

Their Krakken has been on my mind for years...

That kraken

I've really loved my blofeld. If I didn't need the range for some of the things I do, I'd get a used module version and one of those little rockband keyboards. Easily under 5 bills and you'd have a fantastically programeable and portable synth.

Dave Smith Evolver + a midi keyboard, hands up.
The only sub 500$ synth Trent Reznor uses on stage (keyboard version, though)

My vote goes to the Shruthi-1. Best of both worlds: digital waveforms, analog filter. You have to solder it together yourself, but pre-assembled ones go on sale now and again for a bit more dough (There's a dual SVF one right now for $415 or so). If you build your own, you can even customize it with your choice of filter. There's 6 of them now, but Olivier adds a new one every few months. The only downside is that it's monophonic, which may not be an issue for you.

http://mutable-instruments.net/

There's also a couple other threads on budget synths if you search for them.

askthedust wrote:Dave Smith Evolver + a midi keyboard, hands up.
The only sub 500$ synth Trent Reznor uses on stage (keyboard version, though)

There is an evolver in the bst right now.
viewtopic.php?f=44&t=22394&p=361186&hilit=Stage+hog#p361186

sanfordandsonny: master of the bst

Yamaha PSS series can be had for cheap and I love love love the sounds I get with mine. More "lo-fi" and they have mini-keys.
I have the 470 and I love it because there are no menus/all sliders and buttons, can program your own drum beats, and a ton of sweet sounds.

Plus ~$50 aint bad. & apparently they're good bending platforms.