New battery buying advice

Hello friends..
I am looking at buying an extra battery for my LG Env Touch. I travel most of the time so planning to keep an extra battery in my travel bag. I searched around for awhile and found a Li-lon battery at http://www.dealrocker.com/promotions/overstock/deals for $14.99. I don't know much about cell phone so need your advice before getting into anything. Is it worth to spend $14.99 on a battery? If you know any place where I can buy best quality phone batteries at genuine, please let me know.

Thanks..

It's been two years on this stock LG battery and about time for replacement.  I have found stock LG 950mAh batteries on Amazon for $5 and my wife's enV3 for $2.  Costs have come way down so no reason to squeeze out the most life out of a battery.  I may just buy two to keep one charged for when ever on the road or in the air.  Anyone else needing a new battery, don't pay 15 or 20 bucks some places are selling for.

Yeppers, Just ordered my replacement from Amazon. It was $4.95 with free shipping. 

Will do 

^ Does the new battery represent the bars correctly?  For example, my current battery, which is from June 2009, will show all 4 bars when fully charged.  After it wears down, it'll go down to 3 bars and never back to 4 bars unless recharged.  So that's all good and normal.

However, it gets tricky after 3 bars.  It'll sometimes quickly go down to 2 bars and even 1 bar.  Then back to 3 bars.  And when it blinks, indicating near empty, after a while, it'll go back to 1 bar or even 2 bars.  The way I've been observing it, 4 bars is full and 3 bars means half full.  I hope the new battery addresses it so that it decreases linearly.

Interesting.  So maybe I've had a somewhat defective battery all this time.

The thing that makes the biggest change in battery life, by far, is sending a picture text message.  It'll often drop 1 or 2 bars, and then a little while later, after it's done, go back to 2 or 3 bars.  While it's at 4 bars, however, it'll stay there, unless it was close to dropping down.

It sometimes feel that the batter strength meter is somehow tied to the signal strength meter. 

My battery must be partially defective if you or no one else has seen it fluctuate by 2 bars (in either direction) in a short period of time and only very rarely see it fluctuate up by 1 bar.