In this study, the authors propose a scheme based on Stackelberg game for price and power control in threshold-based relay network, where the source transmits message to destination with the cooperation of a relay, in the presence of an eavesdropper. The relay gets revenue for transmitting the source information and the source profits from the cooperation secrecy rate. The source needs to pay for the amount of power allocated by the relay for transmission of source data to destination. Threshold-based relaying is considered, where the relay can correctly decode the message, only if the received signal satisfies the predetermined threshold. Maximal ratio combining scheme is employed at destination and eavesdropper to maximise the probability of secure transmission and successful eavesdropping, respectively. Unlike other works to date, the authors have maximised the utility of relay and source, with allocated maximum power constraints at the relay node, using Stackelberg security game scheme. The closed-form optimal solution for price and power control is obtained, for this leader–follower security equilibrium game model, with the help of convex optimisation.