A wise man once said "There is no such thing as a free lunch". There is NO magic driver that will make a cheap sound card sound like a $800 system. "You gots to pay to play..."
I don't know what your application is, or what level of quality you are looking for. You can buy a SoundBlaster Live! Value Edition card for $50-$75 that will make some pretty nice sounds, and do some respectably clean recording, given its price range. The Diamond Monster cards sound OK as well. I don't know of any other sub-$100 cards that will match them.
Hope that that answers your question....