1. A computer-implemented method comprising: extracting product descriptors from a product page; receiving a result of a search for prices of the product based on the extracted product descriptors; generating, using the result of the search for prices of the product, a price comparison result for the product displayed in the product page; identifying, using the price comparison result, a product with selected attributes; generating a buyer button, the buyer button including a direct link to the identified product with selected attributes; generating a browser toolbar and the product page contemporaneously in a client browser, wherein the browser toolbar includes a seller button, the buyer button, and the price comparison result for the product displayed in the product page; and generating, in response to operation of the seller button, a product listing on a marketplace, wherein generating the product listing includes determining a product category and a product description from the product descriptors extracted from the product page; wherein the preceding steps are performed by a computer processor.