My roll-up door is the top-of-the-line from Overhead Door, 18'x10' high. You do NOT want to know what it cost! But it's steel both sides, insulated, yadda yadda.
There's a few roll-up door websites that have online quotes; the shipping is what kills you though.
The type of roll-up door many 'self storage' places here use is simply one sheet of metal, corrugated horizontally so it'll roll up on itself. I'm planning to use one like that between the garage and shop space. One online quote showed about $250 for a 12'x8'-ish door, but shipping was over $200. Ouch. That type is probably limited to 8' or 10' wide; seems like it would get flimsy if wider.
It's tough to get prices on doors without talking to a salesman; you might have to bite the bullet and talk to a local outfit. Good thing is they can install it, and if they don't do it right you can blame them; if you DIY and screw it up, you might be SOL.
c.