"Sales price" or "purchase price" means the full amount received from the sale of property delivery charges, manufacturers excise tax, and any other additions to the selling price. Finance charges, carrying charges, or any other addition to the selling price as a result of deferred payments by the purchaser are excluded from the sales price or purchase price and are not subject to sales or use tax. No distinction is made between sales of new, used, or trade-in equipment for tax purposes, all being taxed on the differences in the sales price and the amount allowed for a trade-in.
35 Miss. Code. R. 4-10-02-104