Physical layer security is an emerging security area that explores possibilities of achieving perfect secrecy data transmission between the intended network nodes, while possible malicious nodes that eavesdrop the communication obtain zero information. The so-called secrecy capacity can be improved using friendly jammers that introduce extra interference to the eavesdroppers. Here, we investigate the interaction between the source that transmits the useful data and friendly jammers who assist the source by \masking" the eavesdropper. In order to obtain a distributed solution, one possibility is to introduce a game theoretic approach. The game is de¯ned such that the source pays the jammers to interfere the eavesdropper, therefore increasing the secrecy capacity. The friendly jammers charge the source with a certain price for the jamming and there is a tradeo® for the price. If the price is too low, the pro¯t of the jammers is low and if the price is too high, the source would not buy the \service" (jamming power) or would buy it from other jammers. To analyze the game outcome, we de¯ne and investigate a Stackelburg type of game and construct a distributed algorithm. Our analysis and simulation results show the e®ectiveness of friendly jamming and the tradeo® for setting the price. The distributed game solution is shown to have similar performances to those of the centralized one. This work was supported by NSF CNS-0831371, and was supported by the Research Council of Norway through the project entitled "Mobile-to-Mobile Communication Systems (M2M)".