O’Hara Associates sells golf clubs, and with each sale of a full set of clubs provides complimentary club-fitting services. A full set of clubs with the fitting services sells for $1,500. O’Hara sells the same clubs without the fitting service for $1,400. Assuming that the golf clubs and the club-fitting services are separate performance obligations, estimate the stand-alone selling price of the club fitting services using the residual approach.