netbook batteries - a lottery?

[#1]

Are OEM netbook batteries just a lottery?
I ask because my netbook (AOA 150-Aw) battery is knacked, and I've been eBaying replacements ... apparently identical spec batteries (7200mAh supposedly, from UK sellers) range from c.£25 to c.£130 ...  the latter being about as much as I paid for the whole device in the first place ...
any experiences or recommendations anyone'd care to share?

[#2]

Never had a problem with mine. I did suffer a dud one a laptop years ago which I bought 2nd hand. Bought a replacement for £70... then found them on ebay for £25 
My netbook however hasn't had any problems although I only bought that in Jan Feb last year.