I was looking for a high quality gym bag to carry all of my gear in last year and King Kong bags came highly recommended.
After 13 months of weekly use my original Kong still looks new. I carry my lifters, my belt (proper leather, not easy to fold nylon), various accessories, and a change of clothes with room to spare.
You can get 10% off pretty much whenever by messaging them on Facebook, but 15% off is 5% more than that. You don't have to be Scott Steiner to know that that's a better deal!
I got one of these top gym/sports bags to carry spare runners/boots.