I have a different point of view. Whether you save money sewing depends on the kinds of clothes you're making instead of buying. I like nice clothes; I'm hooked on beautiful fabrics and fine workmanship which can get quite costly in ready-to-wear.
I have a wrap top on my website that I just made with a $3 remnant and a few hours work (of course I don't look at it as work because I love to sew!). You can't even get a top at Walmart for $3! I made a corduroy skirt, copying a $150 Theory design that I saw at Saks for about $6.
Of course there are times I splurge, like on a black cashmere knit ($50/yd.) to make a sweater coat (total cost about $150). But I love it and I know I'll wear it for at least a decade, if not more.
I'm a self taught seamstress and I believe in trial and error. Just try to cut down on the errors. It takes practice to be a good sewer. I suggest you start with a very simple design, maybe an a-line skirt with a waist facing instead of a waist band. Then take it one step at a time and go to the internet if you have questions. I'd be happy to answer any question!
Each time you make a new garment, try a new sewing technique, i.e. waistband, invisible zipper, inset sleeve, etc. Before you know it, you'll be sewing like a pro.
Also, set yourself up for success by choosing fabrics that are forgiving. If you make your skirt with a nubby tweed any little sewing mistakes will blend right in. Natural fibers are easiest to work with because they iron so nicely, half the battle to a professional sewing job.
Fit is always and issue with home sewing. Unless you're willing to get a book outlining patter alteration, I'd suggest purchasing a pattern according to your largest part (hip measurement or waist measurement for pants and skirts, bust measurement for dresses and blouses). Cut the fitting seams (usually the sideseams) 1" wider, then baste the garment together and try it on and adjust. Fitting as you go is the fastest way to a good fit. Or, make your garment out of practice fabric first, then transfer the alterations to the paper pattern. Again, make it easy on yourself at first and pick simple designs with few seams.
Good Luck and Happy Sewing!
Nancy, Your Devoted Sewist
To get started, all you need is a straight stitch sewing machine, either a zig-zag option on your machine or pinking shears to finish seams, chalk or a pen for marking, scissors, a ruler or tape measure, pins and needles--keep it simple and inexpensive at first.