A dear friend of mine got married (her 2nd, his 1st) a few years ago. It was a DIY, a few suggestions...
She had the ceremony and reception in the same hall.
The bridesmaid dresses were cocktail type dresses bought at Macy's on sale for $40 each.
No photographer. She had disposable camera's on each of the tables. One of the relatives had a high end digital camera and took pictures of the ceremony. I also took tons of pictures for her. She was able to put together some great albums for herself and parents.
She had a cash bar. Soda was free to the guests.
The cake was a sheet cake bought at the local grocery store. It wasn't the most beautiful cake, but it sure tasted good.
Just out orientaltrading.com for decorating suggestions. Candles are inexpensive and can be quite elegant, however, make sure there are no safety issues. For something less formal, you can do alot with balloons.
Congratulations and good luck!