Hi Justice! If you have a small guest list and a great backyard space, then a backyard wedding could save you a lot of money!! However you also have to think through all the additional rental costs that could be involved, such as renting tables, chairs, linens, plates, glasses, silverware, speakers, etc.
Here's a great article that goes through the pros and cons and has expert planning tips:
My opinion is backyard weddings CAN save $$$ however they are MORE work for either the couple &/or "hosts" (who owns the yard/property). They can be a lot of fun either way. My oldest daughter got married at my home ~ I worked VERY hard to make everything "right" (from planting flower & shrubs, to picking up the flowers, cleaning the house and getting everything set up and ready AND then all the clean up afterwards). I also paid for most of the out of pocket expenses with the exception of the photographer, her dress & the chairs she rented. My brother lived next door at the time and when his daughter got married the following year said "NO WAY" was his wife going to work that hard for their daughters wedding (she got married at a county club near by)! When my youngest daughter got married this past spring she got married at the oldest sisters home/lake property (& even though they hired more things it was still a LOT of work).