If it's inside the house, might check into X-10 stuff. They've been doing the home automation stuff for decades, and might have something to suit your needs, and it all works together. I haven't looked at it in years, but wasn't terrible expensive, and they had tons of information on their website on how each product works, and connects with other products the sell. Worth a look, just to see what's available, and maybe some ideas, and search the web for something more specific for your needs.
Have seen some automotive remote/receivers on surplus sites for around $20, not sure about the range, or how well they play together. Maybe for after market car alarms or something.
I tend to leave RF circuits to the experts, usually I find it frustrating to get them tuned, and a little disappointed in the final project, if it even works. Having the proper equipment would probably make a huge difference, but I seldom have a need for such an investment.