What you pay for three-piece crown molding depends on factors including the type of molding you select, the amount of space to be covered, the job’s difficulty and the professional you hire. Most professionals charge about $4 to $8 per linear foot for material and labor. The average cost to have a professional install crown molding on 500 linear feet usually ranges from about $2,000 to $4,000. If you want to tackle your own crown molding installation, read more here.