My achieving sims use to get like this after awhile. If you are gardening for income stop or splice down all the plants just so what you harvest can go in the fridge. Don't harvest them until you need them. Snack on the fruit or veggies (if it's a good enough quality) and see what moodlets pop up.. or cook with it. If you have packs that you can make things like herbal remedies.. use them in your game play instead of selling them. Same goes for potions if you have a scientist. If you paint don't sell them, collect them. I'm choosy about what painting I keep around... but keeping a bunch of masterpieces will drive the bills up.
Buy drinks for the crowds at the bar. Pretend you have money to throw around. Get a maid gardener and the butler.
If you deck your house out with the pricey stuff the bills will soon put a dent in it.
I usually have to send my sims back to work (usually crafting) after a bit or decide what to start selling.
How did your sims make all their money @R3imiu?