The RD20SL is a popular choice for both beginner and experienced players, and it typically sells for between $500 and $800 in good condition. However, since your guitar is in mint condition, you may be able to sell it for closer to the higher end of the range.
Here are some factors that could affect the value of your guitar:
* Condition: The condition of the guitar is one of the most important factors in determining its value. Since your guitar is in mint condition, this will likely increase its value.
* Age: The age of the guitar can also play a role in its value. The RD20SL was first introduced in 2015, so your guitar is relatively new. This may also increase its value.
* Originality: If the guitar is original and has not been modified in any way, this can also increase its value.
* Provenance: The provenance of the guitar, such as whether or not it has been owned by a famous musician or has been used in a notable performance, can also affect its value.
If you are looking to sell your guitar, you should start by doing some research to get an idea of what it is worth. You can also consult with a guitar expert or a music store to get a professional appraisal.