Robot Inventor #51515 worth

Based on the catalog information provided on your screen, the Robot Inventor #51515 is listed with a used value of $499. Since the second item, "LEGO Robot Inventor (51515-1) (Mindstorms)," is unpriced in the catalog, I cannot give you a specific valuation for it. For the #51515 set, the typical value is driven by its condition and completeness, and you can compare the current asking prices against the sold values shown on the page to see how it's trading right now.