Thank you for submitting your item for appraisal. This appears to be a postcard with a Keith Haring autograph and drawing, dated 1988. Prices for Keith Haring autographs have suffered in recent years due to the high number of falsifications. The postcard in your possession has value because of the provenance. I would advise you to write down the story and add the exact date, situation etc.
The estimate is based on similar drawings / autographs by Keith Haring offered or sold at auction.