I used a striped cotton pillow ticking I picked up at JoAnns. With a coupon it came to about $3 a yard. It's finer and more tightly woven than regular ticking, and I love the combo of florals and stripes!
You'll need some sort of spring steel hoop boning. There are several kinds, but I tend to use a medium strength variety that consists of two bands of spring steel coated in plastic. You can find it at corsetmaking.com. They have another kind that is similar, only coated in buckram, but I find the plastic stuff is easier to cut and is a little stronger than the buckram stuff. I know that Farthingales has heavier duty spring steel boning, but I've never used it so I can't say much about it. You can figure out how much you'll need by adding together all the circumference measurements you came up with when you drafted your hoops (add an extra 1" for each hoop to allow for overlap). To my displeasure, corsetmaking.com doesn't carry hoop connectors, so I purchased mine in person at Lacis.
I also got my boning cutters ages ago at Laci's for the dirt cheap price of $10. They cut through the plastic coated steel like butter, but may not be as effective on the super heavy duty stuff.
You'll also need enough bone casing or grosgrain ribbon wide enough to act as channels for your hoop boning. To figure out how much casing you'll need, find the width of the fabric in your pattern, then multiply that by the number of bones you're using.