Back when money was tight I got a job working in an office so I needed some decent clothes for that. I sewed myself some blouses out of fabric I got at Goodwill or on clearance, and I found a deep red satin blouse for $3 at a resale shop. It had ugly buttons, but I've always had a button box so I found enough matching gold buttons in my stash to replace the ones on the satin blouse, and ended up with a very nice blouse for work. Even if all you know how to do is replace buttons, fix hems, or mend seams you're still ahead of a lot of people.