I bought a light setup a while back for my 870 express. It had a curly cord that connected to the forend so when you grabbed the gun the light would turn on. I got it for like $30. The reason I am telling you this is because I thought I got a good deal at the time but it was junk. The last thing you want to do is buy something that is going to break in a couple months especially as a gift. Also the piece they sent me to connect the light to the magazine tube extension did not work so I had to purchase another piece to get it on the gun. What I am getting at is if you are looking for a light setup I would not suggest buying something cheap. The only light setups I would recommend for a shotgun is the ones that are a whole replaceable forend with a light in it. They are (NOT CHEAP). Just my thoughts. I know I did not answer your question and to be totally honest I do not know of a less expensive good light setup for shotguns. Good luck. I am sure he will be happy with whatever you give him.
From my cold dead hands
If guns are outlawed only outlaws will have guns