A Bill of Sale acts as a receipt for both parties. The seller can use it to prove that an item was sold to the purchaser "as-is", and the buyer can use it to prove that payment in full was given to the seller. It also provides a sale date to both parties, which can show when the responsibility of the item was transferred. Both the purchaser and the seller can use it as evidence of the price paid for tax purposes.
A Bill of Sale should only be used for "as-is" purchases, when payment in full will be made once the item is exchanged. It expressly disclaims any warranties that relate to the quality or fitness of the product.
If the item happens to be insurable, you may need to provide documentation to prove that you are the legal owner of an item, or that you are no longer in possession of the item. A Bill of Sale, if completed correctly, can be used as proof of ownership.
Free bill of sale forms are offered on this page. A bill of sale is a legal document made by a seller to a purchaser, reporting that on a specific date, at a specific locality, and for a particular sum of money or other "value received", the seller sold to the purchaser a specific item of personal, or parcel of real, property of which he had lawful possession.