I bought a few extra hoops with my machine when I bought it. I also bought a few others afterwards when there was a great deal at the dealership.
The best money I spent was to buy the metal/magnetic hoop - you use magnets to hold your fabric in place. I almost always use this one, if at all possible. I also almost never use the smaller ones. I mostly use the embroidery function to make quilt labels or embroidery bags with it.