Please help with this practice question. Thank you.

Chrono24 hosts a marketplace for used watches. The site has 100 potential buyers of a used Rolex and 100 potential sellers. Buyers value a valid used Rolex at $2000, and value knock-off used Rolexes at $500. There are 3 types of sellers: 20 of them are selling knock-off Rolexes and will sell at any price above $300, 40 of them are selling valid used Rolexes and will sell at any price above $1300, and 40 of them are selling valid Rolexes and will sell at any price above $1800. Buyers cannot differentiate between sellers of valid used Rolexes and sellers of knock- offs. If all 100 potential sellers of watches put their watches up for sale, what price would the average buyer being willing to pay for a used Rolex? (Write answer without the dollar sign.)