The Rolex Datejust is a true industry icon and the best-selling Rolex model of all time. First introduced in 1945, the Datejust permanently established the standard for date displays on wristwatches, and it has been a cornerstone offering within the Rolex catalog ever since. Due to its long history and continuous production operations, a considerable number of examples exist today, many of which can still be purchased on the secondary market for less than $6,000. 
One of the great things about the Rolex Datejust is the remarkably wide range of diversity that exists within this single collection due to how long it has been in production and its enduring popularity all over the years. Along with both trendy and vintage models, you will also find Rolex Datejust watches in a variety of different sizes, crafted from a number of different materials, and fitted with an impossibly diverse assortment of different dials, bezels, and bracelets.
Not all Rolex Datejust models can be ordered for under $5,000 and generally speaking, modern Datejust watches and those made from valuable metals will typically be the most expensive. However, there are still quite a few different references – especially those made between the 1960s and 1990s – available for less than $6,000, and you can even opt for the iconic two-color model, which features stainless steel and gold components
The Rolex Air-King is another historic model that can often be seen for well below the $6,000 price point. The Air-King collection was first officially launched in 1957, but the actual first use of the ‘Air-King’ name on replica Rolex watches dates all the way back to the 1940s. Although the series was briefly discontinued between 2014 and 2016, the very long production cycle of the Rolex Air-King means there are still plenty of products available in the secondary market at very reasonable prices.
The longest-running reference from the collection’s history is the ref. 5500. This historic model holds the distinction of being the first official Air-King reference from 1957 and it remained available all the way up until the early 1990s. Vintage Rolex prices can often be extremely expensive, especially for inaugural references. However, because of the incredibly long production period of the ref. 5500 and the numerous examples available on the market today, it is actually one of the cheapest fake Rolex models currently available.
What’s more, the huge majority of 34mm Rolex Air-King models can be found for under $5,000, giving you the option of either having a vintage or modern watch. All Rolex Air-King models produced up until the collection’s releasement in 2016 have case diameters of 34mm, meaning that the vast majority of references from the collection’s entire history will be on the table at a very inexpensive price.