you have hit upon one of the theoretically most challenging parts of marxism. the relationship between use values (what you are just calling value here, meaning the practical use that people get out of a commodity) and exchange value (usually represented as the usual monetary price you purchase it for in the market) has been a common criticism of marxism since Capital was published. my advice is to ignore it at least until you are thoroughly grounded in the basics and possibly far longer than that unless you feel particularly drawn to the issue. for day to day organizing it is not something that will come up.

many papers and dissertations have been written by people far smarter than me (and probably you, too) on this, so once you have read Capital and the other marxist basics there will be plenty of material for you to engage with on all sides of the debate. for example, i have had this piece on redsails in my bookmarks for few years.