Where is the cheapest place to buy insulation?

The cheapest place to buy insulation depends on the type you need and whether you can buy in bulk, but for most homeowners the lowest prices are found at big box stores and local building supply wholesalers. Home Depot and Lowe's consistently offer the cheapest retail prices for common fiberglass batts like Owens Corning Pink and Johns Manville, especially when they run buy-more-save-more events or offer free blower rental with 10 or more bags of blown-in insulation. For contractors and larger jobs, local building material suppliers like ABC Supply, 84 Lumber, or Carter Lumber are often 10 to 20 percent cheaper than retail because they sell by the pallet. Online, Amazon and eBay are rarely the cheapest due to shipping costs for bulky insulation, but insulation-specific online retailers like Insulation4Less and IDI Distributors can beat local prices for rigid foam and spray foam kits. The absolute cheapest method for attic insulation is to use the Home Depot or Lowe's free machine rental program. You pay only for the bags of GreenFiber cellulose or Johns Manville fiberglass, which costs about $0.60 to $1.00 per square foot to reach R38. Also check utility rebate programs. Many electric utilities offer $200 to $500 rebates for attic insulation, which effectively makes it the cheapest place to buy.