It all depends where you are located as well... what costs one place will cost more or less somewhere else. (due rental costs, wages, etc.). As well as the size and weight of the animal, how long they will be under, etc. Most quotes are usually on the high end as well.
I had surgery on my dog (med sized about 22lbs) that required removal of a small unattached lump on his snout... they quoted me almost $1000, but in the end it cost around $600. The huge cost was the anasthesia they figured about 30 minutes, but it took only 10 minutes and plus I opted out of the blood work since it was only recent that he had it done.