Cheapest Timer light switch.

I would find some motion activated ones, instead of timer ones. We have them in the bathrooms here at work, and I think it clicks off after 5-8 minutes. I honestly forget, because I started taking the elevator to another floor for any times I had to use the stall instead of the urinal. Nothing like just getting relaxed and the dang lights going out and having to wave your arms around hoping they come back on. But for home use in areas like that, it would be great. We also have them in the offices on our floor. Automatically cut off after 5 minutes of no motion.

Even basic dimmers are $12-15 each. One with a timer is going to be more. I thought about doing this for my living room, kitchen, and the kids playroom, since those are the ones that seem to always be left on. The living room has 5 can lights and another fixture on the switch. The playroom has two fixtures with 4 bulbs each, and the kitchen has a pair of fixtures, one a fluorescent and the other with 5 bulbs. I ended up just using dimmers instead because I couldn't find one with a timer or motion sensor and dimmable at the time, but it has been several years. Plus all of them were 3 pole and I wasn't sure how a sensor would work with those.