How much should I expect to pay to have old siding removed, and new vinyl siding installed?

I’ll probably buy and have installed 10 windows, too. Price by the square foot on the siding.

When replacing aluminum siding with vinyl siding is the old siding removed first?

I plan to replace the aluminum siding on my house and replace it with vinyl siding. I am wondering if the old siding is removed and new foam insulating sheets are placed prior to the vinyl… Is it difficult to remove the aluminum siding?