In California. I own a 3 bed 1 bath 1,100 sf home. I don't need to use the whole house for myself, but I don't want roommates. I am interested in exploring options to create rental income or reduce my living expenses. I'm not interested in doing something unless it makes sense financially. My backyard is big enough to build a new dwelling and there is an alley along the back side for access. I would build a fence bisecting the lot, so practically it would be two separate lots with separate access, although still legally one parcel. Many of my neighboring properties have this setup. I have priced out building a traditional dwelling to rent out back there and the numbers don't seem to pencil out too favorably.

I considered building an Accessory Dwelling Unit of traditional construction, moving in, and renting the main house, which would rent for about $1,400 a month. ADUs have minimal permit fees and no more owner occupancy requirement due to new CA state laws. Contractor buddy says it'd cost about $200k, seems too expensive to be worthwhile.

I want to explore cheaper alternatives which I could live in and rent the main house. I may want to move back into the main house one day, so I would want the alternative to either be something I could rent out, something mobile that I could sell, or something so cheap I don't care. Some ideas so far:

1. Pre-fab tiny home you can order from places like Home Depot.

2. Buy tiny home one wheels, maybe a used one.

3. Build something myself. Not crazy about this as I don't want to spend a bunch of time building something and have no experience.

4. Trailer or RV. Seems kinda red-neck, not too into this.

Does anyone have experience or advice for something like this? What are the best options and around what final cost would I be looking at for something livable? Thanks!