I'm on the same page as Rachel D. Check out thrift stores, yard sales and garbage picking!! I also love to go to different places that have great background scenery. For instance, my husbands family has a cottage up at a lake and in the back yard was this old, run down, paint peeling, red, barn like shed. I put my 8 month old son in jean overalls with no shirt in front of it with a vintage dog pull-toy and got fantastic pics from that. A neighbor up near the cottage also had this old wooden swing hanging from a tree and I put my daughter in a pretty L. sundress and just let her have fun on the swing and got some beautiful pics from that too. I hate those props they use at those studios in the malls, I like things that are really different. I've actually just searched on the internet to get ideas and then went and found things on my own either free or cheap like thrift stores.
BTW, if you've never heard of the website www.freecycle.org you should check it out. It would be a great place to acquire things for props for free. If you want more info on it, send me a message.