I bought a plain dress in Big W - simple, striped red dress which was only about $10. I decided to add a little embelishment to dress it up a bit.
I added a big, black button, threaded with some coordinated ribbon I had (scrapbooking places have a lovely selection of ribbons).
I added some bows to each sleeve.
There you have it, a lovely, semi-christmassy dress...
Not quite as thrifty as my second-hand shop finds, but just another idea to dress up something simple.