I got married two years ago and did exactly this.
The amount you have to spend on a good photographer is insane. The mid priced photographers seem to be someone with a website, a mediocre camera and a tendancy to chronically over/under use photoshop. Theres a very good reason they don't command top dollar.
In my opinion its too much pressure to put on one person but if you can get some friends and family to all bring whatever cameras they have, you will get plenty of photos between you. I had three friends with an interest in photography and some very nice kit and it worked really well. The photos turned out far better than many I saw in professional portfolios.