D50 batteries

[diffusedmind]

I was looking at batteries for my D50 on Amazon, and some of these prices seem too good to be true. I'm looking for a battery that's either the same or higher capacity (I just want backup batteries).

For example: Apogee 1600mAh for $6 (http://www.amazon.com/EN-EL3-Lithium-Ion-Capacity-1600mAh-Battery/dp/B000GHG45C/ref=pd_bbs_5?ie=UTF8&s=electronics&qid=1198985929&sr=8-5) - there has to be a catch with a battery like this, will it even work in the Nikon charger?
Nikon EN-EL3a for $25 (http://www.amazon.com/Nikon-EN-EL3a-Rechargeable-Lithium-Ion-Battery/dp/B0009K9Q2E/ref=pd_bbs_2?ie=UTF8&s=electronics&qid=1198985929&sr=8-2) - more or less guaranteed to work, does it have higher capacity over the regular battery that comes with the D50 outfit?

These $6 batteries are tempting, but if they're frauds, then i'm not even bothering with them. Anyone have experience with these batteries?

[K1W1]

The original batteries in the D50 were EN-EL3 1300mAH. They should not be used. There was a recall on them and if you have one get on to Nikons web site and follow the links to arrange a free raplacement.
The next batteries were EN-EL3a 1400mAH.
The third battery that works is the EN-EL3e 1500mAH that was introduced with the D200. The EN-EL3e has three contactors whereas the other two batteries only have two contactors each. The D200 uses the third contactor for recharge information but the D50 ignores it.
The EN-EL3e will give you up to 1000 shots per charge depending on how often you use the flash and how often you fiddle with images on the LCD.
Now to answer your question.
The originals are LiION batteries. They have a life cycle of 1000 charge / discharge cycles so at $25.00 it will cost you 2.5 cents per charge. At $6.00 for a fake of indeterminate quality (lets say 500 cycles just for the argument) it will cost you 1.2 cents per charge. If you get less than 250 cycles you will be going out backwards.
Personally I would buy the real thing if it's real and on ebay that is a very big if anyway.

[diffusedmind]

Yeah, I saw the recall on Nikons site, but I checked the serial number (as per their website) and it said my battery was not affected by the recall. I see what you mean by the off-brand batteries possibly being fakes; maybe i'll just pick up the legit Nikon batteries. Thanks for the advice. :)