One of the best gifts I ever received was a Saitek battery recharger. It handles both alkaline and rechargeable batteries. I also had a Buddy-L recharger briefly, but it lacks Saitek's LCD display that tells you what's going on. I used to use Radio Shack rechargeable batteries, but alkaline batteries provide more power and are cheaper.
I alternate between two sets of 2 AAA batteries at a time, so that I can immediately replace the old batteries I'm recharging. I usually recharge the batteries in my Pilot as soon as it gives the low battery warning (and I've synced up with my Mac!). A new battery gives just over 3.0 volts, and each recharge brings the battery to decreasingly lower maximums. Eventually, the charger will tell you that it can't recharge the battery. At that point, I throw out both batteries and swap in a new pair. Even with very heavy Pilot usage, I'm still only on my 3rd and 4th set of batteries in 5 months.
I think you can find the Saitek recharger for around $50 and the Buddy-L (also branded by Emerson) for $25. Of course, you can use the recharger for any AAA, AA, C, or D batteries, so there's a good chance that you'll save enough money to pay for the charger (AC power is significantly cheaper than batteries).
BTW, make sure you have your Palm device in the right battery mode. If you go to a Memo Pad record and enter Shortcut Dot 7 (that's the shortcut character followed by a period followed by the number 7), it will toggle the mode and show you the new mode (make sure it says Alkaline and not NiCad).