This paper presents two small test systems for power system economic studies. The first system is based on the original PJM 5-bus system, which contains data related to real power only, because it demonstrates results based on the linearized DC optimal power flow (OPF) model. This paper suggests some modification to the original data, as well as new parameters related to reactive power such that AC-model-based simulation is possible. The second system is based on the original IEEE 30-bus system, which is an AC system, but it does not have economic data such as generation costs and transmission network limits. This paper suggests some reasonable values for generation costs and transmission limits. For both systems, economic studies based on LMP methodology are given for benchmark purposes.