My fiance and I are having a casual immediate family and friends only outdoor garden wedding. I need a great dress that won't cost a lot?

Congratulations! I found two very inexpensive wedding dress options from http://www.jcpenny.com. They are both under $100, you can't beat that! These are both to the floor style dresses. Your local Burlington Coat Factory would also be a good place to look. They usually have a formal dress section with deeply discounted gowns. 

Congratulations on your upcoming wedding day!  I listed a number of inexpensive wedding dress options.  For an outdoor, garden wedding I love the knee-length dresses and provided two below for you to look at.  If you prefer a floor length dress I'd check the sites on the dresses below and also consider looking into consignment shops in your local area.  I wouldn't suggest purchasing a wedding dress from ebay.  Good luck!