Hi Kim, I hoping this video wil help you build your deck - https://www.youtube.com/watch?v=AmqiH95S3ik
What material were you considering? I think you'll find that you would be hard pressed to create anything cheaper than the pressure treated lumber decking most building centers sell.
Using pallet wood or other found material will rot out in short order and become dangerous.
Whatever you decide, Lowe's has a great, free deck designer tool you can use online to come up with your design.