Most of our pastures have 12 x 12' loafing sheds. Couple others have larger sheds.
We use 6-8" dia used utility poles for corners. Then use pressure-treated yellow pine 2 x 6's and 2 x 4's for framing to hold the "galvalume" ribbed tin sheets.
You can see a variety of our sheds on our website. Just click on the photo galleries (we have several).
On the average, in our area, a 12 x 12' shed with sloping roof (8' to 7' high) is running between $800 and $1,000 for labor & materials. Two men can put one up in 8-9 hours (at least that's what ours around here do).
None of ours have sustained any damage even with 50-60 MPH periodic winds througout the year. Lot depends on direction of wind. I might add that on our 12 x 12 loafing sheds we do not run tin all the way up to top--leave about 6-12" air space to allow some of high winds to bleed through the structure: this also makes the shed a little cooler in summer. My guess is that our sheds might survive 60-80 mph winds???? Knock on wood!
Hope this helps!