At first glance, the synth looks less than mediocre. They're small, and usually they aren't in great condition because theyre so old (1982-1983). It was originally designed to sound like an actual bass guitar and replace a bass player in a band, but it didn't really do that too well. The sequencer is a pain to program, and you'd be wasting the rest of the possible sound spectrum if you wanted it to just sound like a bass guitar.
It became popular by using the accent function on certain notes, and tweaking the filter and the accent knob while it plays, creating really squelchy and random sounding effects.
Nowadays, their price can range from around $800 to $1500. There are emulators and clones, but purists say that only a 303 is a 303.
1. Get yourself a drum machine (909) and start making acid music.
or (and i'd much rather you choose this instead of choice #1)
2. Sell it to me, in which case you can forget about the price range that is listed above, and I'll take it off your hands for $50.