It sounds a bit high, but a lot can depend on the rates in your area and what is needed to facilitate the water supply lines. I'd recommend getting another bid or two.

I felt that I was overcharged. I should have used a wrench to put in the faucet, water lines, existing disposaler, and new 4inch plastic tube to existing disposaler. sigh....I was had for 420 !!!! for 30 minute job !!!!
Initial quote was 1020 !!! then 600 then 400 and I had to pay for trip charge of 40 if he didnt do the work ! I should have just bought a bit of plumbers putty , pipe sealant & the plastic tube myself...argh.