Depends on what you are going to haul, but like Smokey, I bought the HDX 4-pack from Home Depot for ~$14. Strapped my 17'+ canoe to my buddy's Xterra this year and it didn't budge on our trip from MD to WV, about 3.5 hours of interstate, winding mountain roads, and a rough gravel/dirt "road"/trail.I just bought a set of 4 at Home Depot the hdx brand, I used it just 2 days ago for a treadmill and the treadmill was not going anywhere. I believe they cost just around $15 US dollars.
Those are exactly what I use.I bought these http://www.tractorsupply.com/en/sto...table-ratchet-pack-of-4-500-lb-safe-work-load
sure they are more expensive but that retract automatically, store cleaner and still have a 500lb work rating. (I haul sport bikes). they are only like 6-7 feel long though.