I'm a graduate student and he's an architect (if you don*t know anyone who is either, this translates into "we have tonnes of college loan debt and are very poor") and we paid for the entire wedding ourselves. We managed a Saturday evening wedding in June, just 20 minutes from New York City, on a mere $12,000. How we did it:
1. We culled the guest list mercilessly. From an initial 180 guests, we whittled it down to 130 invitees. Of those, 90 guests attended. The line "but we've known so-and-so for years!" from our parents wasn*t good enough a reason for a couple to attend. If you haven't spoken to them in 10 years, a wedding isn't the place to start. Considering that you can run up to $100 pp, cutting 50 people from our list saved us 40% of our budget.
2. Use professional vendors that work from home. All three of our day-of vendors: our photographer, florist, and DJ, are freelance and work from home. This allows them to offer the exact same professional service that other vendors provide, but at a fraction of the cost. As I said above, our florist Karin could quote as a price that was unbeatable, and she didn't compromise on the quality or quantity at all. Most of the time such vendors are a lot harder to find because they aren't listed in bridal magazines or you can't walk by their office front and stop in; but they are worth the hunt, trust me!
3. Bargain hunt. Use Ebay. Take advantage of store sales.
4. If you*re crafty, make it yourself. There are numerous online websites that will help you make your own invitations, decorate your veil, or arrange your own bouquets.
5. Cut out things that don't mean much to you. We didn*t do OOT gift bags, a videographer, a limo, favors, personalized napkins/matchbooks/champagne glasses/cake knife-- and nobody missed them. Splurge instead on things that matter to you: we put 70% of our budget into just three things: the reception, my dress, and our photographer. Just a word of advice: what most guests remember most about your wedding is going to probably be whether or not the food was good.
6. A lot of people debate on whether table cameras are worth it. Personally, I am glad we did it. While we did get a lot of blurry shots when people tried to take photos from too far away, we would've missed out on a lot of great photos if we hadn't done disposable cameras.