The other day I order this off amazon. There are a few different model and flavors. The one I'm reviewing is
http://www.amazon.com/gp/product/B00FPHTPSGHypario® uv5r Two-way Radio Battery Case for Baofeng Uv-5r ,Uv-5ra,Uv-5re ,Tyt F8 F9 ,Vitai Vt-uv3 Vt-uv9r Two Way RadiosPrice was $7.98 at time of this posting, and product was eligible for free amazon prime shipping.
Good:price
extended length makes the little uv5r grip better in my hands
designed for use with rechargeable AA cells (they run at 1.2 volts)
it works - I hit a few repeaters and said hello with locals on VHF
BadBottom of case does not snap together as expected. It doesn't fall off when on the radio, but could easily snag and catch if holstered for example.
I might remedy with some PVC tape, but then that's sloppy when it's time to recharge the AA cells.
Cannot use standard 1.5volt alkaline AA without a little mod (see below). This isn't a show stopper, but the engineer in me thinks a range of voltage could be tolerated with a smarter designed radio, but I'm not an electrical engineer...
The plastic is actually cheaper than that on the radio itself. I wouldn't bet on this being around in 10 years.
There's a LOT of info on using these on Miklor's site.
http://www.miklor.com/uv5r/UV5R-FAQ.php#BatteriesScroll down to section
"6.8 AA / AAA Battery Cases (UV5R series)" The price is right, and this allows additional power options for the radio. Additionally if you already have rechargeable AA batteries as a prep this is a tiny investment. I plan to keep this handy, but probably won't use for all the time, since I'm worried about destroying it from repeated attachment and removal cycles.