A bundled product represents more than 2 products being able to sell as a single unit of products at a specific price. When selling a bundled product, a seller can make it comprise either a tying product(s) and a tied product(s), or products with different brands (the principal and the subordinate or equal products). And a telecommunications company sells a bundled product by bundling its own wireless internet product with the latest modeled netbooks manufactured by famous computer makers. The discussions having been made over bundled products up to now mainly focus on the bundled products selling in the broadcasting and telecommu- nications areas. And, even relevant studies have concentrated on economic effects caused by bundling, calculation of prices of proper bundled products, and regulations of bundled products, Some studies on bundled products have been conducted in the management perspective, focusing on consumer response to bundled products and consumer sentiment, Various kinds of bundled products are expected to continued to be released, but laws and regulations applicable to the bundled products have yet to be established. Therefore, it is necessary to discuss how to resolve disputes over bundled products between interested parties. In the event where a supplier of a tying product directly purchases a product from a supplier of a tied product, and then a seller only sells the bundled product, if (ⅰ) the products are bundled under the responsibilities and rights of the supplier of the tying product; (ⅱ) the seller never engages in bundling; and (ⅲ) the seller does not agree to take any inventory liability of the products, the supplier of the tying product should be fully liable for the inventory of the products. But, if the seller leads the bundling and contracts product purchase agreements with multiple suppliers (the principal and the subordinate relationship, or equal relationship) to sell the bundled products, the seller should be liable for the inventory of the products. In the event where a seller emphasizes a tying product and neglects any explanation about a tied product in selling a bundled product, or in the event where a seller puts something only advantageous on advertisements and is silent about the disadvantageous, thereby giving a negative impact on a bundled product, in order for such an action to fall under the illegal deception accepted by Korean legal theories and judicial precedents, it should be as in the following case: interested parties should have not struck an agreement or should have struck an agreement under different terms and conditions if they had known the facts. Therefore, if a seller who has excellent information power strikes an agreement with the other party under deception by falling into silence about important information, the other party who is an weak party may avoid the contract. When there is any mistake in the main part of a tying product, and when there is no serious fault of a consumer about the mistake, it is possible to make full avoidance. But, when any error is not found in a tying product, and when some error is found in the part of a tied product and can be corrected, is it right to make full avoidance? If any errors of a sold tied product are not as serious as in achieving the purpose of an agreement: neither if a tying product does not work well due to any error of a tied product, nor if any error of the object is not able to be repaired at an inexpensive cost, partial avoidance is deemed to come into effect on some part of a legal action. Therefore, partial avoidance causes the effect of purchase and sale agreement on any product (for example, a tied product) with problems occurring during the agreement period to become null and void retroactively. But in this case, the effect on any product without problems still remains. As an effect of avoidance, relevant products should be returned, and unjust enrichment gained in the purchase and sale process should be returned as well. And, legal principles and product liability of a bundled product are so unclear that it is desirable for a seller to force a manufacturer or a supplier to take out product liability insurance. In this case, the insurance premium should be determined within a reasonable range of amount. If the insurance premium is not based on the risk level of a product and the sales of a product, but is set as an excessive amount for a product with no risk, such an action of determining the premium is considerably deemed to be abuse of a business position among unfair trade practices, because it is considered to be excessively disadvantageous to the manufacturer or the supplier.