Getting Married With Barely Any Money

Hi My name is Dominique ,I am 23 years old and my fiance is the same .We have two small children one of which is very sick(he holes in his lungs and seizures).So money is extremely limited.My fiance and I just started trying to get our lives "right" with the Lord,so we have decieded to go ahead and get married.Does any one have any tips on how to throw a nice yet very cheap wedding.Or where I can get a wedding dress without giving up a arm or a leg?Any help with be GREATLY VALUED .
GOD BLESS,Dominique