I volunteer for an organization that sells tickets every year for an annual event. An email goes out that basically says "Your tickets are in your folders, please sell them or return them back to the volunteer coordinator" Those who want to sell them, do. Those that don't, return them.
Just because your boss gave you tickets doesn't mean you are obligated to purchase or sell them. Act as you mean to go on. Return them to your boss and let her know that you won't be participating.