The brick used in home building is sold by the 1,000. So if you are looking for brick on a custom home the builder will usually give you an allowance or a few samples in the same price range to choose from. For instance if you are given an allowance of $325 (per 1,000) you choose a brick that is $350 , and your home requires 11,000 brick, your change order would be :
350 - 325 = $25 x 11= $275 + builders mark up
%. usually 15 to 20%.