If you like your processors to be guaranteed good overclockers, then one of the easiest ways to buy one from Silicon Lottery, a company that pre-tests the overclockability of processors before reselling them. They do come at a premium though, especially when they're at the bleeding-edge extreme of performance. In the case of the newly released Intel 9900KS, which is guaranteed to run at 5GHz across all cores right out of the box, Silicon Lottery has a special version that is guaranteed to go further and hit 5.2GHz on all cores.
The price? $1,2000.
Typical 9900KS chips will set you back around $550 depending on whether you can find stock or not. If you buy it from Silicon Lottery, it'll be $600 with guaranteed long-term stability at 5GHz. You can have it delidded (removing the IHS for better cooling) for an additional $50.
From there, prices go up dramatically.
For a chip that can guarantee a 5.1GHz overclock, the price is $750, with the very special few (just three percent of all 9900KS can do it) 5.2GHz versions, costing $1,200 for the privilege. Delidding is an optional extra in each case, carrying a $50 premium.
These prices might seem extreme, but many of the options are sold out, so clearly this is a service people are willing to pay for.
How much over retail would you be willing to pay for a guaranteed overclocking chip?