Here are some of the factors that could affect the value of a 1938 John Deere Model AR tractor:
* Condition: The overall condition of the tractor is one of the most important factors in determining its value. Tractors that are in good condition with minimal wear and tear will typically sell for more than those that are in poor condition.
* Location: The location of the tractor can also affect its value. Tractors that are located in areas where there is a high demand for them will typically sell for more than those that are located in areas where there is less demand.
* Desirability: Some John Deere tractors are more desirable than others. For example, tractors that are rare or have unique features will typically sell for more than those that are more common.
Based on these factors, I would estimate that a 1938 John Deere Model AR tractor in good condition and located in a desirable area could sell for around $2,500. However, it is important to note that this is just an estimate and the actual value of the tractor may vary.