How do you tell if princess Diana beany baby is valuable?

To determine if a Princess Diana Beanie Baby is valuable, first check its tags for errors, as rare tag variations can significantly increase value. The condition of the Beanie Baby is also crucial; it should be in mint condition with no stains or damage. Additionally, verify if it has the correct date of retirement, as the Princess Diana bear was retired in 1997. Lastly, consult current online marketplaces or collector guides for recent sales to gauge its market value.