Who knows? There's no way any of us can answer that question accurately.
How many estimates do you have?
What exactly are the diffs between estimates?
What are the reputations of the shops you received estimates from?
What have previous customers of these shops said about the quality of work?
I can prolly find you some good ol' boy in the backwoods of Georgia who will do that job for a lot less that $1000. If price is all that matters, it's easy to find someone cheap.