As long as your wedding gown is not made of silk, it may be washed by hand in a clean bath tub (you will have to remove hem dirt). Depending on the level of hem dirt, this is not a hard job but requires some time hand-scrubbing the hem with a white sock soaked with water and Tide or other good detergent. For best results, fill half-way up a clean bath tub with warm water and some Tide. Soak your gown for an hour, then, sitting on your bathtub edge, clean the hem and other spots. If the sock is not working, advance to a soft brush. 

Take breaks as necessary! Examine the entire hem, neckline, underarms, etc., to make sure you have cleaned all visible dirt. Rinse and hang. If the gown has wood splinters in it, you may need to use tweezers to remove them. Rinse the gown well and hang it to dry with non-metal hanger. This removes almost all wrinkles; if you desire it steamed, some cleaners will steam it for a fraction of the price they will clean and steam it. Or you can steam it yourself.

Hope this may of be some help.