(b)Charges by service providers. A provider of sales agent services shall charge sales tax on the total fee or commission charged to the seller for whom such provider acts as agent, including all expenses that the service provider incurred in making the sale (for example, advertising fees, rental fees or printing costs), whether or not the service provider paid tax on such items at the time of purchase. Where a sales agent charges a commission to the buyer of property, such commission is not taxable as a sales agent service. However, the total amount of the commission paid by the buyer is taxable as part of the sales price for the purchase of the tangible personal property. If a seller that is represented by the sales agent is engaged in selling the property in the regular course of business, the seller is liable for collection of sales tax from the buyer measured by the gross receipts from the property sold. If the seller is making a "casual sale" pursuant to Conn. Agencies Regs. § 12-426-17, tax does not apply to the sale of the property by the seller to the buyer. In either case, however, the sales commission paid to the sales agent by the seller is taxable.