The poker table makes money. I had 4 elders living together and they sat around playing all the time while their money went up. It is too addictive though. One time I took a group of knowledge sims to the cemetery so they could fulfill 'see ghost' wants. On the way to the taxi heading back to dorm, I kept hearing that kaching sound and forgot I hadn't removed it. One sim was slow to the taxi and while waiting I noticed their less than 3,000 simoleans was dropping. I had to pry her away from the table to get out before they lost it all.

Poker tables are IDEAL for a bandatron business for that very reason, in a previous version of Heimlichbourg, the Geldschmidt family made a HUGE fortune by running a casino, with just two employees, one charismatic sales sim at the door to talk people into paying the high admission fee, one to tidy up (just set up staff-only entrances to both restrooms and a gentleman sim can clean the ladies' room or vice versa). Abraham Geldschmidt, the family patriarch and a family/popularity sim, could just hang out in his posh office above the casino floor, looking down on his domain and fulfilling his friend wants by using the phone or schmoozing with some select clients). Another winning item for that is the bubble blower (great for a starting home business to build up some capital- you can build a "bubble house" with a nicely appointed room with a couple bubble blowers and locked doors to keep the bubble heads from getting into your family's rooms elsewhere in the house ). Not sure what those bubbles do to sims, but I know for sure they're not going near my kids until they sleep it off! But the best of all is a hottub surrounded with snapdragon bouquets on pedestals. With their needs continually bumped up by the bouquets, sims will sit in the hottubs for hours and hours, chatting away, building up their friendships and the owner's wealth at the same time. As I rule, I actually have the government run those businesses. In order to jack up the price a bit more I'll also include a couple swimming pools (men only, women only and gender neutral) and gym/sauna facilities. You get something like the Roman baths, a real community institution that encourages social cohesion (you'll be amazed how many best friends your playables have after spending all that time soaking and swimming with random fellow citizens) as well as catering to people's needs..

I'm not sure if anyone has said this yet but... digging for treasure. Even if you just find a few bones they'll be a bit more valuable collectively and you also get to fill in vacation memories if you find a treasure chest or a map.

Those kleptomanical sims could make even more by lifting the computers, TV's ect.

I used two houses in Strangetown, the empty Grunt house and the similar one next door for graduating sims needing someplace sort of temporary. The houses were enlarged and remodeled to hold 8 sims. The first male and female graduates would each take over a house. The rest of graduates would go to their respective gender home. Usually it was small, separate bedrooms or a large, shared room on second floor. The first floor had a large livingroom-study section, large eat-in kitchen with a small living area for the 'overseer'. Sims could finish up skills, start their jobs, work on relationships, and/or date their significant others. The properties were large enough for parking, swimming pool and other outdoor activities, while the second floor could also have a pool table and darts. Once a sim was ready to marry and move out, they would have a large wedding party which was always top'notch. Then they would move out. After the move out, the sim in charge would send them a check to cover the purchase of their home from the monies they earned from their job, painting and whatever else brought in simoleons. Sometimes orphaned teens or occasionally an unfortunate abducted sim would move in. There was always some one there to babysit while the parent went to work. No need for a nanny, maid, gardner or any one else. They shared all the chores, including cooking.

There is another venue to try, as well-a pawn shop.

With all the valuable merchandise (or not) that your sims have been buying, they're desperate for fast money.

Open a pawn shop to cure their problems! You don't need much for inventory.

Once you buy an empty building, and set up shop, every time someone comes to check it out, pause the game, click on the customer (make playable for a few seconds) and check out their inventory. If you like what you see, relieve your customer of it, and place it for sale in the shop. Make the customer unplayable afterwards, of course!

You can make decent money from this. Sims are such suckers they'll happily buy back what they just pawned!

Yep! I used the mind control mirror a lot. Back then..in the days hehe.
Since many customers came often, I would take back whatever I had sold to them.

How devious! I wish there was an actual way to set up a barter system though... townie Sims usually have random items in their inventory, right? Why couldn't they offer those items in exchange for purchases? It doesn't seem like it would have been THAT hard of a interaction to include... I wish barter actually worked- it would be perfect for pawn shops or medieval marketplaces, or so many other things!

...I wonder if there's a mod for that? /me goes to look.

A simple way to do it is to make the townie playable for a bit (simblender can do this), exchange things from the inventory (if you want an interaction you could try give gift (came with seasons I think) if the relationship is high enough) and then return the townie to his/her former townie status.

Bartering works just fine Zarathustra. My second hand dealer pays townies 10% of the items in their inventories. if they walk by her house, they must want to part with these items, yes? Haha. They don't have to stop and be greeted. I use the sim manipulator, it adds make selectable to every sims pie menu, so i just click 'make selectable' empty their inventory across her yard -some of them come with a huge pile of junk. Then add it all up and pay them roughly 10% with Christianlov's wallet controller. That is in my integrated hood.

On my island commune hood they are all best friends, no townies so they just give gifts for whatever it is they want. Your fish for my tomatoes kind of thing.

That is also a good idea for a yard sale: make all passing sims playable, then take out what they have in inventory-voila! You have your stuff for a yard sale!

Well just came up with another one.

First remove you burglar alarm and move all the stuff you don't want to lose to a room with out a door and then get all the Aspiration rewards objects and place them were the burglar can get them. You must call the police after he/she has stolen some items to get the simoleons.

Haven't tried it myself yet, but hustling pool is mentioned in the University Prima guide.
A business with just a band playing for tips works rather well too, and you don't even have to use an admission fee if you don't wanna have too much money right away.
Also, making the kids bake a lot of cakes in their little ovens, then sell them. A way to get around child labour laws. Better than the lemonade stand (although little children are more profitable as free farm labour).

I think even without hacks a sim can lend another sim money- I think the relationship has to be high. Consort Capp was on his Son in law's community lot and when I clicked him the option appeared to lend him money...I could be wrong but I had all expansions and stuff packs when this was available.

No, that would be a hack, unless it said 'pay off' that shows up sometimes when one sim is mad at the other.