There are solo money making objects that you can use. The payout for each one scales based on a specific skill but you can go ahead and use them with no skill at all if you wish. Some examples are the canning station (cooking skill), the telemarketing phones (charisma), gnome bench (mechanical), etc. There is at least the one for each skill. (Body took a while, but eventually they added a pinata in for that. So strange LOL)
While these objects are used alone you do get a bonus to your payout if others are engaged in the same activity (on a separate object) Their skill does not effect your payout, your skill does not effect theirs. You can start and stop whenever you want and don't need to organize with anyone.
You do have to remember to click the object when the task is done to complete the task and get paid.
The payout is lower than you'd get with the group money objects (that you can ONLY find on money lots), of course, but they are easy to do when you are multi-tasking. Canning for example is starting the sim at the task and waiting 5 minutes for it to finish. The group machines are all mini games.