Rolex watches vary greatly in price, but you will be lucky to find one less than about $5000 (£4000) for a basic steel Submariner model.
Rolex make a phenomenal amount of different models and specifications and the price can go up dramatically depending upon the specification. For example a Submariner in 18 Karat gold with diamonds can easily cost as much as $20,000 (£18,000).
A good way to find the price of a Rolex watch is to visit Yngoo.com (alternatively for UK Rolex prices visit Yngoo.co.uk). This site has an app built in that allows you to set an upper and lower price range and search for the best selling watches in that range. You can also seach for the cheapest watches avaialble within that price range, and even the best reviewed on Amazon.