Are you making the infinity scarf as a rectangle, twisting the ends after bind-off and sewing this together, or are you trying for the moebius scarf? Both are infinity, but the moebius is done on a 47"+ needle that is wrapped around itself and knit in the round. These require two different cast-ons. Check the internet for moebius cast-ons; there are a few with Cat Bordhi being the authority.
No one has mentioned the KnitPicks Harmony/Knitter's Pride Dreamz interchangeables. They may not be the Cadillac of knitting needles, but as an all purpose set, they are just fine. I like the fact the needles are shorter (4.5") compared to the 5" inches of the other brands.
The Cadillac of needles is probably the Signatures which don't come as interchangeables, yet.
As for the Boye. My set is 40+ years old, gave them to my daughter and she doesn't use them either except to store unfinished knitting projects.
Try a "yarn buddy" or create one by inserting a plumber's friend (plunger) thru the skein and sticking the suction cup to a turn table (lazy Susan). Now pull. The yarn should not double back upon itself.
Watch every video you can to learn how to manipulate dpns. Then see if your needles are compatible with your yarn. Bamboo needles "grip" yarns more than metals so you don't lose the stitches as readily. Wood dpns can also be somewhat slippery. I understand the carbon fiber dpns (Blackthorn & Knitter's Pride Carbonz) grip yarns better than bamboo.
Check to see if your library has Sharon Turner's book "Teach Yourself Visually Knitting" which walks you thru every aspect of knitting with straights, circulars and dpns. This Visual series also has one on Circular Knitting by another author.
Check Ravelry.com for hat patterns.
You need at least 40 ounces of yarn, but this doesn't tell you how many yards you need.
Do test drive the Hiya Hiyas before purchasing to see how you like their feel with various yarns. Please remember that metal is more slippery than wood or bamboo and some yarns seem to fly off our needles more quickly with metal. Sometimes we want a little drag with needle and yarn. That's why we have so many different needles.
My "go-to" needles are the Knit Picks Harmony, but I do use KA bamboo, Crystal Palace bamboo, Addis in metal & bamboo. And I definitely switch between lace and regular tipped needles depending on the yarn.
It's all right to be a yarn snob. You will discover while looking at projects on Ravelry, it is the yarn that makes the item spectacular. I, too, use inexpensive yarns for baby blankets that go to Europe. But for myself, I will spend more then $3.99 for a skein of yarn. Now become a needle snob. You will feel so much better in the long run and your projects will be happier.
The library should have Nicky Epstein's "Knitting on the Edge" which guides you thru various types of edges for knitting projects.
Check to see if your library has the "Cast On, Bind Off" books. There are now two. One has 53 methods, the other 200+ versions. This will definitely keep you busy.
If you can locate 600 grit sandpaper and jewelers emery cloth, then you are set to repair you needles. The fine grit smooths the surface rather than removing the outer layer of wood or bamboo. And polish with unscented beeswax or wax paper
Try the Norwegian purl method. Once mastered, it is very fast.
Now you see why we should be reading charts and symbols instead of all these words!!! When charted the symbols show exactly where to repeat and how often.
Thank you for letting us know. I am tempted to purchase some.
Sharpen chop sticks, sandpaper to a smooth finish and you'll be fine.