There's a big difference of performance IN Axims, and that's the thing to consider, if you're buying a card specifically for that purpose.
At the moment, the Lexar is the most reliable, with a decent price point. You probably won't like the results you'll get with a SD card that costs less.
You can see the comparisions we had at this address:
www.choirguy.com/memory.pdf
Good luck.