I own Kreg's track saw and table. It's great if you're doing a lot of sheet cutting. But if you're just getting started I'd recommend a regular circular saw. You can always clamp a straight board or level to a sheet to simulate a track.
A couple of tips: You'll need a lot of clamps. Don't spend much money on tools until you know what you're going to build. It's really easy to get caught up in precision and having everything cut perfectly. This is important in finish work, but for everyday stuff you don't need to worry about it.
If using hand tools is of any interest to you, I highly recommend the Anarchist's Design Book, Anarchist's Tool Chest. All by Christopher Schwarz and available from his press Lost Art Press. I discovered them via a comment here a few years back. His basic philosophy is woodworking for regular people to make stuff that are going to last and usable. Lost Art Press' website has a lot of book samples and full books in PDF form. It's worth checking out.
I think a Kreg track saw is a better place to start than a circular saw. I think the cleaner, more precise cuts you get with the track saw will help encourage a new woodworker.
What I have is a circular saw (specifically a Skilsaw). There’s a sled that you clamp on for use on the Kreg tracks. When I have it set up like that, is it similar to what I could do with a panel saw?
More or less. A panel saw combined with the track it is intended for will have often have a "zero clearance" strip along the track to prevent a lot of the wood being torn up when cutting. So, nicer cuts.
For me, having the sled "built-in" on a true panel saw makes for a less awkward experience using the tool.
It would be one thing if I went back and forth between using the circular saw and the panel saw but I truly haven't touched my circular saw in maybe ten years now.
What do you think about combination squares? They look super useful and the common advice seems to be get a Starrett or maybe a PEC. Less expensive options probably aren’t a better value.
A couple of tips: You'll need a lot of clamps. Don't spend much money on tools until you know what you're going to build. It's really easy to get caught up in precision and having everything cut perfectly. This is important in finish work, but for everyday stuff you don't need to worry about it.
If using hand tools is of any interest to you, I highly recommend the Anarchist's Design Book, Anarchist's Tool Chest. All by Christopher Schwarz and available from his press Lost Art Press. I discovered them via a comment here a few years back. His basic philosophy is woodworking for regular people to make stuff that are going to last and usable. Lost Art Press' website has a lot of book samples and full books in PDF form. It's worth checking out.
Good luck!