OK, you've come to the right place.
Make the invitations yourself. We did ours using Publisher and had a photo of ourselves looking happy (and very drunk) on the front.
Get friends and family involved in the practicals. I catered one sister's wedding (they had the reception at their house) I've driven cars for other siblings. My sister in law took the photos for my wedding, so they had an intimacy you don't get from a disinterested professional.
Try a Sunday wedding, they may get the venue cheaper. we had a very posh venue (Trafalgar Tavern in Greenwich) but had it on a Sunday, so came in at half the price of a Saturday wedding.
If anyone in the family cooks or sews, get them to do the cake or dress. Failing that, Marks and Sparks do wedding cakes very cheaply. I decorated ours with flowers from MIL's garden.
Disposable cameras given out to the guests get some fantastic action shots.
We chose all the music we wanted from our music collection and burned it onto 2 CDs. Whenever we want a romantic evening, it's these we get out rather than the photos.