What drives the price
Roofers price by the square — 100 square feet of roof surface. A 2,000 sq ft single-story home is usually 22–28 squares once you account for pitch and overhangs.
Steep pitch, multiple stories, and complex rooflines with many valleys and penetrations add labor. A second layer of old shingles that has to come off adds disposal cost. Decking that's rotted under the old roof is the most common change order — expect $70–$120 per sheet of replacement plywood.
What a fair quote includes
Tear-off and disposal of the existing roof, ice-and-water shield in valleys and at eaves where required, synthetic underlayment, drip edge, new flashing (not reused), ridge vent, and the shingle line by name.
If two quotes are $4,000 apart, the difference is almost always in these line items — not the shingle brand.
Before you sign
Get three quotes on the same written scope. Verify liability and workers' comp insurance directly with the carrier. Never pay more than a third up front, and never sign an insurance assignment-of-benefits form at the door.