If you want to go cheap, get some Rachet straps at Walmart. Look for the 1500lb ones.
If you want to go for the most awesome straps ever, order webbing straps from warbonnetoutdoors.com.
I love the Warbonnet straps, but have hung just fine with the $6 walmart straps. 300 lbs.
Avoid the Eno Slapstraps, they are worse than worthless.