That was a rough quote for a 60 mil liner, but it also was when I renovated my pond in 2008. IIRC the quote was given in 2007.
Liners went up a bit the past couple years. Looking at some old info, a 45 mil x 50 x 100 Firestone EPDM was about 1600 bucks, plus shipping. (I would pick up) New price from the same company is 3,400.00. That's quite a price hike in about 3 years. My only option tho.
I see a few places that are selling EPDM roofing for pond liners. Some claim to be able to "clean it up to be fish safe". I am not sure what the "real" difference is between the two. Probably worth an investigation tho.