I hear ya, honestly i'm not an expert either..just around the house stuff. Really for this type stuff it won't matter what brand you buy , just buy a brand name.
You don't use it like say a builder would, and like me you're not skilled enough to know the difference....it's not until after i've used something a matter of time that i understand the difference in quality and features of tools.
They will have a cheap blade and should be a blade for lumber (instead of more, finer teeth for cutting plywood) but you won't notice on this type of lumber and yard project...save buying a good blade for the next project. I still use whatever came with my circular 10 years ago for this type stuff, though did at some point put a better blade on when i got to using it to make projects around the house and needed a finer cut. For this you don't even need a saw horse, just 2 wood scraps so when you cut through your blade doesn't hit the ground.
I buy decent stuff, my neighbor drags home 20 year old beat up tools from yard sales and does twice the job i do on things, takes him a bit longer and 1/2 the times comes over and borrows mine but I'd rather be like him!
But the first decent power tool I had I was given on our first home, a circular saw, and i used a miter box for other stuff. It's not until you find yourself doing a lot of repetitive cuts, miters or numerous that you think dang i could have done this in 30 minutes as opposed to hours. So if i had to start anywhere i'd start at a circular..and it's safer for a 1st timer than a table saw, then a miter, then table saw.
Though a circular saw is something that as a first tool you'll use a long time if you take care of it, so maybe others have suggestions on what's out there now. Major things i notice with circulars are left or right (which side the motor and blade are on), ejection port, and the base. Some like steel bases for durability, i really like thick cast aluminum like on my older porter cable as it's very rigid and i know dead on the distance to the blade (but in a harsh environment can crack instead of bend).Things like lasers are a bit handy in hindsight but usually on cheaper stuff not all that accurate....still handy to quickly line up then fine tune though.
With a circular plan on a couple of clamps as well you'll use those and scrap straight piece of wood or a straight edge to get straight cuts easier, not so much on this but more so any future project you plan.
Either way google on safety. Stuff that seems really simple in hind sight you think dang i shouldn't have done that.
