With our frame we used four 6' 1" web straps for our cooler and dry box support with 8 strap sliders which was about $10.
If you want to really accessorize your frame, add the NRS cooler mount and NRS dry box mount ($65).
If you want to add comfort add the NRS seat bar ($95) and seat. There are two types of seats you can add. One is small and durable and easier to stack mutiple frames on top of each other for traveling ($66). The other seat is very comfortable and can get in the way a little more when transporting a lot of items on a vehicle. If you want the comfort, the bigger seat is worth the money $90).