Kits always seem to be expensive, @orchidsonabudget! And I never see why they would be any better or simpler than just following a beginner's pattern and using thr yarn and needles it recommends!
Is it the Knitty Gritty book you've bought? I found it really good as an intro to knitting. As for the needles and wool - some people prefer bamboo/wood to the more common coated metal ones. Bamboo and wood are less slippery, which is helpful for a beginner as it makes it harder to accidentally lose stitches off the needle.
What yarn thickness you'll need will depend on what you're making. The needle size needs to be appropriate to the thickness of yarn and vice versa. For example using a much thicker yarn than the pattern specifies would make the item bigger than it was meant to be. Using smaller needles will make the knitted fabric tighter and more rigid, whereas using bigger ones will make it looser, floppier and more holey iyswim.
But you don't need to worry about any of that for now. As a beginner, just use the needle size and yarn weight that the pattern says!