When Jim Lett started his window and door business, A.B.E. Window & Doorin Allentown, Pa., he did everything himself -- including the books. Soonenough, however, Lett began to outsource his bookkeeping. He still does, ata cost of between $450 and $500 a month. Generally, costsat home improvement companies that outsource bookkeeping range from $200 to $1,000 per month.