When you have a list of quotes for anything, whether insurance or for your roofing work it is vital that you compare them on a like for like basis. This is why it is also important that you research the product you are looking to buy before you begin your hunt for the best free roofing estimate you can find. If you have a quote from one company offering you two layers of roof materials and an offer from another company only offering one layer, it is immediately obvious that the latter is going to work out cheaper because they have lower cost of materials and lower labor costs.