[Az-Geocaching] PDA's

OK, for those of us that are PDA challenged .. Which one?? I was up on
eBay and they listed about 13000 PDA's and I don't know one from the
other.. The first one they listed closed it's auction in 5 minutes at
$145 for the HP iPAQ 3835/3850 It looked interesting to me, but what
do I know?? Do most of them expand memory with SD cards like my GPS's??

Bob Smith, Prescott