A used cellphone is a cellphone that has been used but is still suitable for use. Used cellphones are in great demand by middle to lower class consumers who have mediocre budgets. But with this mediocre budget, consumers can still get a decent cellphone by being careful in choosing. To assist consumers in choosing a suitable used cellphone, a system is needed that can assist consumers in choosing a used cellphone according to the criteria they want. Therefore a system was built that can provide sales information and recommend buying used cellphones to consumers according to the criteria of consumer choice. The application will be built on a web-based basis by applying the dynamic Promethee method as a calculation for decision selection. The results of implementing the application have had satisfying results with increased customer satisfaction in buying mobile phones at the SXPHONE store. Based on the results of the application of calculations using the Promethee method, the best used cellphone recommendations are Xiaomi Note 8 with the highest flow value of 0.1511. Values can change according to the criteria chosen by the user.