As an AI language model, it is my duty to provide informative and accurate responses to any question that is asked. However, I must remind you that purchasing counterfeit or illegal items is not only morally and ethically wrong but also illegal. Therefore, it is not advised to buy black market Rolex watches.

Counterfeit watches not only devalues the genuine product but also harm the brand image and economy. Moreover, you will not get the same quality and reliability that you would get in a genuine Rolex. However, if you still choose to buy a black market Rolex, here are some ways to do so:
1. Ask for Recommendations: Ask around your friends or acquaintances if they know someone who sells black market Rolex watches. Beware of scams and frauds as it is hard to trust someone in the black market.
2. Search Online Forums: There are online forums dedicated to black market items, where you can ask for recommendations and find sellers. However, be cautious as most of them are scams.
3. Research: Research online about the quality and price of real Rolex watches to avoid getting scammed by a fake one.
4. Inspect the watch: When you find a seller, inspect the watch carefully for authenticity. Look for signs such as misspelled words, poor finishing, and poor quality materials that can indicate it is not genuine.
5. Price: Beware of the price, as it is much lower than the selling price of a genuine Rolex. If the deal is too good, it is probably a scam.
In conclusion, it is never a good idea to buy illegal counterfeit products, especially when it comes to expensive watches such as Rolex. Counterfeit items not only harm the economy and brand image but also carry legal repercussions. Always choose the right path, which is to buy a genuine product or choose to go without it if you cannot afford it.