If you're a beginner, I think it's helpful to start out with the basics before moving on to specialized stuff.
High speed steel lathe tool blanks are inexpensive, and by grinding your tools instead of buying inserts or ready made tools you will learn a lot about what is needed for different materials and cuts. If you goof up sharpening HSS, you can adjust it until it works better.
Mild steel is all you need, for practice blanks rather than stainless, and it will teach you a lot. True, it isn't easy to get a fine finish on some of the lesser grades, but that kind of difficulty is a blessing in disguise because it allows you to see improvement when it happens. You will learn a lot about feeds and speeds and chatter, etc. as you try to improve the finish on practice bars. These things are all important to experience first hand. It gives you the background to understand by feel almost, what is needed. It is very much more instructive than looking up inserts in a catalog.
High speed steel lathe tools can be made very sharp. It's not necessarily a lesser choice. HSS may not have the wearing qualities of carbide, but is easily re-sharpened and to a high degree. It is true that for some uses carbide is a better choice. But for most everyday use for common steels brass and aluminum HSS is an excellent choice. I think it is ideal for learning, inexpensive and flexible in application.
The first week I started eleven years ago after months of building a lathe and having a lot of expectations and anticipation, I had trouble getting anything but a rough edge on work and was appalled at what I had vs what I hoped it would be. Don't get discouraged by that. It happens to everybody -- particularly with a small lathe. I gradually learned to sharpen better, adjust speeds and feeds, increase work holding stiffness, too, by many small changes to what I was doing -- long overhangs of thin stock don't work well. Turning work between centers helped greatly for some things, etc. etc.
You need to learn your lathe and its capabilities, and don't worry too much if you can't at first get the same results you see in photographs online and in magazines. You will eventually get there as you improve your methods and understanding. Experience is the best teacher.
One place I found helpful for my initial sharpening of tools back then (and is still online today) was Varmint Al's website. He shows lots of interesting stuff for a newcomer and a first lathe. The diamond toolholder also mentioned above is nice (but pricey) if you are trying to achieve a nice finish with relatively easy tool grinding.
Whatever you choose, don't worry too much. You will work it all out in time!