Ouch! Even used slide rules can be pricey. I think I'd stick with the Texas Instruments TI-36X Solar Scientific calculator for about $20.

Being a Palm PDA user, I wish they'd make an AA or AAA battery-powered Palm, but not anymore. I guess the brainy chips use too much power for the alkalines. They all use rechargables and the solar chargers are just too pricey for me.