The total purchase price or taxable price of a vehicle is determined by the certified selling price agreed on by the buyer and the seller, including any dealer processing charges as defined in Transportation Article, §15-311.1, Annotated Code of Maryland, less an allowance for the trade-in. There is no other nonmonetary consideration. The taxable price of the vehicle shall include: The retail purchase price; The shipping or freight charges; After manufacture items included with the vehicle at time of purchase; and Manufacturer rebates. A dealer may not include the cost for any nontaxable items when determining the taxable price of the vehicle. Nontaxable items include: Dealer trade-in allowance; Dealer discounts or rebates; Extended warranties; Mechanical repair contracts; Federal excise tax; Electronic registration fee; and Equipment installed to accommodate a disabled person.