Inexpensive Handhelds for Linux?

Dr. Manhattan asks: "My PDA was stolen on a business trip, and I'm looking for a replacement. I've enjoyed Palms for their simplicity and long battery life, but I'm not afraid to program and I'm considering something that can run Linux. However, my budget is rather limited; $150 is all I can spend. Relatively obsolete tech is fine, but I'm looking for: good battery life (my old Palm could run for weeks on a charge; I'm hoping for double-digit hours), dual expansion slots, all of the onboard hardware solidly supported by Linux. Does such a beast exist in my price range?"