If you have access to the equipment, I have been looking into 3D printing a light gun. There are print files and a part list for the internals that are designed after the console Gun Cons out on the web. Probably the most affordable way to get one atm, just need the skill set to put it all together lol. I think they also sell premade ones, but they cost a bit more.
I have seen some of the “nice ones”, like 200-300 dollars (that’s the “one day”~ right there. lol). And no, I do not have the equipment or access… at this time. I have always wanted to get into 3D printing though. I would definitely be interested in seeing how it looks and works though if and after you have made it! ~would be very interesting to see. I’m assuming you have to solder some components, because snapping all those pieces together sounds too easy (like lego pieces).