If it is YOUR money, it is YOUR money and you decide what to do with it. If it is disposable income, not needed for anything else, you can allow yourself to spend it on items of your choosing, or put it in the bank for something else or gift it or whatever. Noone else can tell you what to do with your own disposable income. If it were jointly-held money, then this is a different story altogether...
If you feel badly about the price you paid, don't divulge it to anyone else. It really isn't anyone else's business, when we come down to it. if you want/need it for your hobby, you bought it. Use it with pleasure!