I try not to start with a cheat so I usually build my own homes. The ones from the gallery labeled "starter" are usually very pretty but they will take most of your starting budget or you must use "motherlode" to buy them. Most have unnecessarily large rooms & you pay for sq. footage so my Sims start out in very tiny homes. Bedroom is only big enough for a double bed and the bathrooms can be just 3 squares, shower and toilet to either side and door in the middle like a "powder room". They can wash their hands in the kitchen sink nearby. Only enough space for just the things they absolutely need. I try to give them better appliances by cutting back on the "pretties" in the home but always include the computer and money earning objects like the easel or the woodworking table.
I have a few families that have never had "real" jobs but got by on painting, collecting, and farming. If you're going the plant route make sure you have high yield plants like roses, tulips, bird of paradise, dragon fruit. If you can get one scientist in the neighborhood to bring back alien plants and grow them, have your Sims visit them and harvest a few. You can rake in the $ by growing those. Tack an enclosed porch on the back of the home with planter boxes and you can grow year round.
One of my Sims just inherited a home and greenhouse from his parents who never had jobs - just gardened and collected - and he is worth around $200K and the money just rolls in now. Running out of things to spend it on.
I feel your pain. Playing just the careers from a $20K start is tough and pets are a big drain on income. I have a struggling couple who just can't get ahead because the dog is CONSTANTLY sick and every time they get some $$, BOOM - vet visit - like every other day. I'm such a softy, I can't even let a virtual pet suffer or give it up for adoption so the unfortunate Gustafson couple will be dirt poor for a very long time.
