I was wondering what the price of a Gtx 660 ti would be for a upgrade on a old computer. I was guessing the used price of one would be $130-150, is this about right?
Howdy. You could purchase a brand new GPU for that budget. Better to choose something like an R9 270, which should retail around $160. It's a rebranded 7870, which is competitive with a 660ti.
http://www.ncixus.com/products/?usaffiliateid=1000031504&sku=94204&vpn=CGAX-R9276&manufacture=Club3D&promoid=1070
This is $160, but I think the offer ends on the 30th. A matter of hours away.
If you overclock it to the speeds of a 270x, it would probably beat the 660ti on a consistent basis. I always preferred the 7870 over the 660ti. Though, they were neck and neck most of the time.