When I got a house, I severely underestimated the cost of bringing it to a “ready to live in” state.
I mean, when I moved it, it was ready to live in, of course, but little things like adding a light to a closet or installing a ceiling fan… it really added up. Plan ahead. The bigger TV for the bigger room is the last thing you need. Make a budget for your upgrades/repairs, and don’t let yourself fall into the “I need this done at move in to be happy” mindset. A floor fan is just as sufficient as a ceiling fan for a few months.
When you live in a rental or an apartment, you tend to not have lots of things you need to own a house, like:
Ladder(s). Standing on a chair to change the smoke detector worked fine in the apartment, but in a house roofs are often higher and you usually have more stuff to do up high because maintenance is on you. You’ll need a good ladder, eventually.
Tools. Every project you take on will need a different tool. Get some basics at move in, but plan on getting some more with time.
Garden supplies. Hose, shovel, rake, pruning supplies. These add up.
Good news is a lot of this is easy to get used in fine condition. Pawn shops, garage sales, etc. Start looking now, before you move in. And be patient to maximize savings. A shovel will be $3 at a Garage Sale and $25 at Home Depot. A hedge trimmer could be $150 at Home Depot and $10 at a Garage Sale or $40 at a Pawn Shop. Take a friend/family member who is a homeowner to help you get these things. And rent tools when you can.