OK, so you're not going to find a lot of hand-made, vintage, one-of-a-kind or small-batch clothing at the mall. What you will find, though, are clearance racks, lots and lots of clearance racks, of indie-style stuff.
So shamelessly troll the consumer zones and pick up some graphic tees, skinny jeans and oxfords from the sale area at the mid-range stores, and from any area in the low-price ones.
You'll also score big at online specialty stores that label themselves "indie" (just search Google) and on eBay, where sellers offer new merchandise for well below retail. Some eBay stores will even customize the clothing they offer, which ups the indie factor significantly.
Hand-made, though, is the Holy Grail, and while you certainly will find independently created clothing on auction sites, you'll find a whole lot more of it at crafter/artist marketplaces like Etsy. Aspiring fashion designers, along with simply creative folks who are handy with a sewing machine, sell truly "indie" pieces there every day, and in droves. Of the nearly 20,000 "indie" results on Etsy, about a third are handmade. It's indie heaven. And while hand-made doesn't always (or even often) mean inexpensive, you can still find some great stuff with lower price tags and a lot more character than at retail stores.
Or, you can sit back, put your feet up, read an obscure novel and let time do the job for you. Trends change in less time than it takes to squeeze into a pair of skinny jeans, so if you're looking at a seriously slim fashion budget, don't sweat it: What you're wearing at this very moment might be "indie" in a couple of weeks.
For more on the indie movement and general fashion and style, check out the links on the next page.