I agree with Allison - don't wait until you NEED something, sure fire way to overpay!
I don't mind thrift stores or garage sales, but I don't usually have time to estate/garage sale most days... but I've gotten some fabulous items there. But I cruise the Buy/Sell/Trade pages and Craigslist almost daily. I look for one of a kind item when possible, and I like an eclectic mix. I'm in the process of planning a room redo - hoping to add another room to my listing. It won't be until next summer when my youngest moves out for college so I have time to plan, search, and redo if necessary.
I often will leave my finds as they are, or redo. I'm not as dedicated or as talented as Huma, but maybe someday! Usually simple redos, recover seats, a fresh coat of paint etc. I've a short attention span!
One tip for money saving - for those of us who live near the US/Canadian border - cross over! The exchange rate isn't quite as favorable for American's at the moment, but it still adds up. And for old items, no duty at the border! I get a lot of great antique sewing machines in Canada.