I see most have covered the basics, the only thing that's up in the air is fabric. The cost of this depends on how much you are ok with spending. JoAnn's has decent fabric that you can use 40-50% off coupons for.
When purchasing fabric, I need to touch it. Some fabric, even the $10/yard at the LQS (local quilt shops) may feel thin. Some fabrics are sturdier. The thinner material will breakdown quicker than the thicker.
You may want to chose your fabric depending on what will be done with the finished product. Will it be dragged on the ground by a toddler? Will it hang on a wall? Good luck and enjoy the art of quilting!