I wandered through 5th Avenue trying to find boots and the perfect denim. There are some more affordable shops (like H&M) dotted in-between the insanely expensive ones. But I ended up doing my shopping at a mall in the suburbs. Same shops, just less crowed. And I got the sale stuff in my size.
The shops here sell denim jeans in every possible size. Waist, length and styles can be picked. It took me a while, but I got the perfect fit at H&M for a decent price. Wish we had this in SA: http://www.hm.com/us/denim-guide#path=2