I don't know how much there is, what kind of condition it's in and prep it will take, and I don't know what you expect to make for your time. That's the key, and only you can answer that.
How much do you want to make, let's say, per day for yourself?
How much overhead do you have (broken down to a daily total)?
How much (reasonable) profit do you want your company to realize off a job of this size?
There is no magical "per sq ft" number. You need to take all of those things there, add them together, and you'll have a total. If you don't know your overhead, you should. Calculate all your business expenses, fuel, cell phones, vehicles, insurance, advertising, etc for the whole year and divide it by the number of days you work per year. You'll have a number that tells you how much it's costing you per day, just to stay in business. Add your salary too....now you'll have a workable number. You know it costs you $XXX to go to work every day for yourself and have a paycheck.
Take that daily number and decide how many days this job will take, and add up the cost for those days... (it could be a weekly number, whatever) Add your profit to that daily number, then add your cost of materials, plus any markup for the materials.
Waaalla! You have a number! ....and this forum has a search feature to help you answer bidding questions that have been THOROUGHLY covered in here! :Thumbs: