I have been in the same boat. For projects where it really matters, I buy better lumber, only using studs and other construction boards where a little slop is okay or easily bent into place.
Having proper tools can make it a lot easier to work with wood you cannot easily source in the dimensions or straightness you require.
You can always buy the necessary tools down the road.
You can do a lot with a table saw. But then you might want a band saw for resawing. You might need a planer for thickness adjustments. A board might warp or not be as straight as you expected, and you might then need a jointer.
For small projects, it won’t cost that much more for you to go with lumber already surfaced on all sides, compared to the hassle it saves. For larger projects, or years of small projects, there will be cost-savings but also flexibility in getting the equipment you need to surface lumber as needed.
Surfaced pine boards are fairly easily available. Beyond that, I also buy small amounts of poplar, oak, and maple locally, and maple and other boards from other suppliers. Some lumber yards and other suppliers can plane wood at request for a small fee, and even if boards aren’t surfaced on all 4 sides, they might be parallel and with a straight edge that can be used along a table saw fence.
In other words, you can look at better lumber for small projects and then still consider the equipment for the next larger project. If you’re on the fence, there’s no need to rush purchasing decisions.