No, you don't need to quit and I wouldn't spend money on online classes, either. Leah Day's website has a lot too offer as do many other websites and utube videos - Bonnie Hunter's patterns at quiltville.com are great. You have found good sources for fabric. My grandmother made fantastic quilts with fabric, a pair of scissors, a spool of thread and some templates. She probably would have used cereal boxes if she hadn't had a SIL who cut them from steel for her. That being said, there is one item I find invaluable as a semi disabled quilter. The June Tailor shape cut keeps my strips straight and done easily and quickly.
I would use the best fabric you can find in your price range. The biggest difference to me is in the clarity of colors. I am using a mixed bag of fabrics for a scrappy quilt right now and the color difference is amazing. I would also slow down the buying and up the sewing. Having too big a stash is not a plus, IMO.
Welcome to the wonderful world of quilting.