I got mine at DSW on clearance. With a $20 coupon from a previous purchase, I pretty much got them for free.
Honestly, I wouldn't recommend spending much on wedding shoes. Nobody sees them. You'll want something comfortable, if you plan to dance a lot (I did!), but really any semi-comfortable dress show will work. Mine were Naturalizer (super-comfy!) shoes that I found on clearance at DSW. I would recommend them!
Another idea is to ask your girlfriends to borrow shoes. I'm lending my wedding shoes to a friend this October. I can easily wear another pair of shoes with the dress I'm wearing to her wedding, and I'm happy to see my shoes get used at another wedding. And even though I have worn them many times since my wedding (that was a key point for me...), I won't care if she never gives them back. They've certainly served their purpose.
Anyway, I'd check out DSW and other clearance stores. Online, look at zappos.com, but their prices can be higher than you'd find elsewhere. My favorite place to get shoes for good prices is DSW, followed by Macy's during a sale.
Vice President and Guardian of the Toilet Brush of POOP: People Offended by Offended People