I have bought all sorts of parts, including batteries on Amazon.
Early 2012, I ordered an iPhone 3GS battery, and one for my RAZR V3i.
Both from the same vendor.
The iPhone battery was OUTstanding.
The RAZR battery was just so-so.
I also got some spare EVO batteries for a buddy.
Both were initially fine. After a few weeks, one acted up.
The vendor shipped a replacement, no charge and didn't ask for the dead one.
Last battery was for iPhone 4.
There were some bad reviews on $4 & $5 batteries.
So, I ordered from a vendor I knew & trusted: Zeetron.
Think it was $7.50 incl shipping, got here in few days, and has been fine 6 months.
All were lithium batteries - not nicad.
Something that makes Amazon purchases harder, is no one mentions which vendor shipped the crummy part.
And the Amazon web site rotates the default vendor multiple times per day.
Advice: read reviews carefully.
Some posters are idiots.
Find state-side vendors you like & stick with them.
Buy from vendors with free or cheap shipping, else it's not worth returning item.
Order multiple items from a vendor, instead of splitting your order 5-ways.
Oh, you'lll like this one:
Ordered a 5-pack of iPhone 4 cameras.
Three were defective when in opened them.

Vendor replaced 'em, but I did have to go to the trouble of sending back bad ones.
(I used one. Anybody need a tested camera?)
