My landlord has been trying to sell the building for 2 years and finally received an offer, but they'll only purchase if I move out. I recently renewed the lease, the move out date leaves 11 months remaining on my lease. He wants me to make him a monetary offer and I don't know how much to ask for. Also, am I entitled to my full security deposit as well, no questions asked (I've read this on a few other forums)? I'm in Chicago.

What you are looking for is an appraisal of your leasehold interest. We can't do that for you. Contact a fee appraiser.

Once you know how much the 11 month leashold is worth, on today's market, subtract the present value of the lease payments you would have to make if you were to keep the lease, that's the buy-out value. You would have course add the appraisal fee.

And yes, demand that the deposit be returned to you as well.

I would ask for 2-4 months rent + moving costs, + differential if you have to move to a place with a higher rent.