The most common form of contract is the purchase and sale contract. A purchase and sale contract is a legally enforceable agreement between one party to the purchase and another to the sale. Use this comprehensive agreement to purchase a personalized home services company that offers non-internet services: example: sports coach or physiotherapist. Menu of appropriate guarantees. Use this complete agreement to buy a home Internet trading store that sells goods of all kinds: no unnecessary formulations, proper warranties menu. Purchase contract for the sale and service of the real estate sector, many options, including the transfer of property or inheritance rights. “The contracting parties,” Mackeurtan writes, “may include in their agreement any provisions they wish, subject to the following restrictions. The aediles say: “Slave sellers must inform the buyers of any disease (disease) or defect (vitium) in a slave and whether a slave is a runaway, a vagabond or not exempt from any noxial liability; All these cases must be explained with an appropriate audience for the slave to be sold. But if a slave has been sold in violation of the foregoing or in violation of what was stated or promised at the time of sale […] we grant the buyer […] legal action for the expulsion of the slave [….] The reason for the proposal of this edict is to overcome the artistic skill of sellers and to help buyers when they are deceived by sellers. However, it goes without saying that a seller, even if he was not aware of the existence of errors […] must nevertheless be held liable.
It is not unfair either, because the seller has been able to inquire about these issues, while there is no difference for the buyer whether his deception is due to the seller`s knowledge or deception.  The parties may vary the normal rules of risk by an explicit agreement in their contract. Courts should not accept that such an exception agreement was implicit in the parties` negotiations, although this is possible. An important question is whether an obligation on the seller to deliver the goods to a given destination necessarily implies an agreement to vary the incidence of risk. The answer seems no. Why would a simple distance delivery agreement mean a delay in keeping the risk in the hands of the seller until delivery? The situation would be very different if the seller agreed to deliver the thing “safely” to the agreed destination.