How to keep up with the money and quest

If you are willing to buy donuts and invest in premium decorations, there is another way. The decorations offer a different percent that can increase your multiplier (the amount of money you get from both jobs and buildings.) I've been playing since August last year and didn't buy premiums until about March. That's one way to increase your earnings.

If you're playing on an Apple device, you can look for iTunes sales and/or wait for a deal from Gil, it's a little cheaper. I never house farmed but I do have a few multiples of some houses just to make it look like a real town.

Get as many characters as possible and send them on long tasks that pay the most money. Do this for a few days and watch your cash grow. I found this way to be far more effective than House Farming.

You actually earn more money by doing shorter tasks sequentially, so long as you can reset them as soon as possible after they complete.

Four one hour tasks pay more in total than one four hour task for the same character.
Two four hour tasks pay more in total than one eight hour task for the same character.
One four hour task and one eight hour task pay more in total than one twelve hour task for the same character.
Two twelve hour tasks pay more in total than one twenty-four hour task for the same character.

There are a few exceptions of course, like Fat Tony's ten hour tub task. It pays more in ten hours than two four tasks, one eight hour task, or one twelve hour task alone.

Okay, that sucks, since I play on android, and there never is a sale there I take?

And since I play on my phone I can't always play every other. So that pretty much sucks. I don't have the money to be able to afford the insanely high prices for the donut items :(

add friends and visit each day. Set your characters on an hour task and visit your friends.
Only build buildings that come with characters not any of the side buildings unless required (prompted for a task).

Position the Simpson house (marge), control tower (burns), kwikimart (Apu) and cletus's farm (perfection) all within the same screen for 45 second tasks and do them. (I find 4 is enough) everyone elses tasks 45 sec aren't at a building. (if you can do that for 10 minutes that will give you a few hundred)

Extra characters should be your goal atm.

Just keep playing and be patient. Those of us playing for over a year now had lots of downtime between updates (a month or more sometimes) building up cash and have loads to spare. There's so much content now, it's impossible to catch up to someone playing this long. It will take some time, but if you keep with it you will get a nice town. It's a marathon, not a race, no matter what you want to do somebody's already done it first. Oh, and I used no hacks or cheats, so it can be done without them.