A slight aside, but over the last few years My PFA strut has held an annual fly in. We used to give a free burger to people who flew in and then charged a nominal sum for any subsequent drinks or burgers. Result lots of Burgers left over and a large loss. So we gave up flogging the burgers and gave them away free, but put an honesty box up. Result embarrassingly large profit. After covering the cost of the buns we donated the rest to the local hospice. So everybody happy and a good turn done as well.
Strange thing perceived value!