Power tools?
Most of my tools I've gotten off Craigslist or from habitat but It honestly depends on your preferences and what you want to do/what wood you are using.
For around the house and light construction projects I have a 5 pack set by black and decker i picked up at a garage sale for $35 4 years ago. Has a cordless screw driver, angle screw driver, a sawzall, etc. Its only 7.5v but has handled every house project and all It needed was a new set of batteries and drill bit kit. This is still my go to kit.
For more beefy construction projects and good all purpose tools you can't go wrong with a scroll saw and a compound mitre. Scroll saw can do most anything a table saw can, takes up less room and can fit in your car - nearly every construction site I've been on this is the tool that gets used the most. A compound mitre can make pretty much any cut and angle on a piece of wood you'd need. My current one I found on Craigslist and only needed a new blade.
I used to have a decent cordless but then bought my current impact driver and that's my go to now alongside a good hammer.
If you're going to be doing a lot of repurposing wood and such I'd get a sawzall, the interchanging blades are great and I can rip a pallet down in 2 minutes without breaking a board. They're also good for cutting out tree branches

If you're going to be doing any painting pick up a purdy brush 2.5" straight, they're expensive but it's my favorite brush and I've had it for years (my father in law swears by them). If you take care of it you won't need another brush.
That's my list:
Scroll saw, compound mitre, impact driver, hammer, purdy brush. I use these almost every day.