Make sure you build it bigger than you think you need. Cheaper to do it right the fist time than to have to renovate.
You need to give a lot more details of your plans in order to get a ballpark. I have a 24 x 52'. It has a single 20' x 14' door. I budgeted $25k for the basics, then planned on finishing (insulating, power, drywall, heat) later. I decided to do it all at once and stopped counting what it cost when I was $10k over budget. I am happy with what I ended up with, but it certainly was a process.