I've rented games to (three different) offices, and about to put one in a personal home for the first time. I think $200-$300 a month is the right amount for a modern game (maybe less if an EM). I would try to charge more if it was getting played more than 1000x per month.

In three of the four cases, the people were either friends, or friends of friends. (In the other case, it was a random office, and I had to consistently bug them to make sure I got paid).

I left the keys with the machine, and showed them how to remove the glass so they could do things like fetch stuck balls or replace a broken flipper rubber.

I would also advise that you do this only within a short distance of your home...and to make sure that you coordinate upfront when both parties will be available for repairs. One office was 20 minutes from my house (which always felt too far...basically an hour trip just to replace a rubber or solder a single wire). On top of that, they were only open from 9-5, so I literally had to skip out on my real job to go make repairs. My longest running office client gave me a keycard, so I would do repairs at 11pm or whenever was convenient for me.

The biggest issue is moving games, and this is probably dependent on each person. I know this isn't the going rate, but even if someone paid me $50 an hour to move my own games, it wouldn't be worth it to me. I'd value that time somewhere closer to $75-$100 an hour (for me) because moving machines is the worst thing about pinball. So...take that into consideration.

I always tell people that they need to be willing to keep the machines for 3-4 months. (You could allow swaps earlier than that, for a fee).

Also I'm going to take you to task for referring to pinball machines in personal collections as "investments". They're not investments, in the same way your car is not an investment. Now, if you want to buy a bunch of cars for the sole purpose of renting them out to strangers, then those are investments.

If you have a machine sitting in your basement, that's a toy. The value might go up or down over time, but that's no different than any other object in your house. If you start using it to make money, then I'd say it becomes an income generating asset.

You can definitely make a little money off of pinball, but it's a lot of time & effort. It's certainly not better a better hourly rate than a good paying job.

I did an event once as a personal favor. It was just two arcade games. So much hassle. The venue had restrictive timing on loading and unloading. I had to rent a uhaul and skip an hour or two of work to get them in.

To make that business work, I think you'd have to charge more per machine than an entire month rental of that same machine. (Which to me is starting to seem cost prohibitive for the customer). And I'd need a truck of some kind. And I'd hire someone else to do the moving.

To do it right, you'd want a bunch of games that aren't in use elsewhere and could be transported with the legs on. You'd probably want a medium sized enclosed truck, with a lift gate, and a coffin dolly (or whatever those are called)...and maybe even the ability to keep the games in the truck when they aren't being used, or a place to keep them at ground level where you don't need to break them down and set them back up each time. Even just breaking down a pin and strapping it to a dolly and then doing the reverse when you get to your location is 30+ minutes per game. 6 pins would be 3+ hours for one person just moving them from where they live to the venue. Assuming there aren't stairs.

I once set up 10 games all at once in a venue that had a flight of stairs. I believe it was 8-10 hours, even though I had someone helping set them up as I was unloading each dolly.

I wouldn't rent NIB games to offices or residences because those games need to go on location immediately. The most money is made in the first few months. It would probably be 2 years before I would consider moving it to a private location.

For Ghostbusters and Dialed In, I think I was (basically) first place in the state to have them on location. Those started out around $40 a day. But that drops off quickly, probably 2-3 weeks.

Every location is different of course. $20 a day might be the top earner at one location, but at another location, it only takes $4 a day to make it the top earner.

If someone starts renting games at their home, they probably aren't going to be jumping around between operators. If the first op does a good job, their next game is almost certainly going to come from the same op.