I believe More Awesome Than You has mods to make money harder to get, and make things cost more. However, your friend will have to look through the forums to find the mods she wants. It will be worth her time, because there are lots of other good mods there.
She might also want to check out Simbiology, Mod The Sims, and Simlogical. There are lots of wonderful mods there for her to sort through.
I can already give my family as much money as I want them to have, the point being that I want them to have less, not more. I want the whole game’s economy to be changed so you can’t sell fish for as much money, you can’t make as much money growing crops, you can’t make as much money selling painting or at work. Etc.
Your friend has bad timing! More Awesome Than You has been down for a couple of days, so I can’t link to the hacks I was thinking of. I’m sure they’ll be back, and I can point her in the right direction then.
In the meantime, one hint she might like. Nightlife introduced the familyfunds cheat. This lets you change how much money a family has. So you don’t want the Goth family to be rich? Just enter familyfunds Goth 100. Now they only have $100, and they’d start working!
If she has OFB, she might like Simwardrobe’s produce and fish packing stations. (Under Sims 2 - Objects - Business Facilitators.) This lets you crate fish and produce up into boxes of 12. You can then set these for sale at the price you like. She can experiment, and set the price low enough to keep the family poor but surviving.
Does she have web access, by the way? Because there isn’t one hack that changes the economy. It will be a lot of small hacks. I know of a few, but if she looks herself, she’ll find even more. If she’s shy, reassure her that many sites allow downloading without registration.