Best replacement battery

[samson_420]

Can anyone suggest one? I know there are a few on eBay, but I know they are all/some of questionable quality.

Anyone buy one that works?

[Hardcore898]

A friend use such a cheap battery, and it works since a half year! Accident? Luck?

But I wouldn't use a low cost battery. I have experience with camera and laptop akkus and they were always bad!

If i require a new battery at this time, I would prefer a second hand battery or an unlabeled.