It's not THAT cheap in the US. I paid $37.85 for five rolls with free shipping on eBay. That's $7.57 each. Provia 100 is $7.99 though without the free shipping from B&H.
I wouldn't have bought it if I had known it was Provia. I was hoping for Astia or Sensia. OTOH, I'm not bothering to sell it or anything. I'll shoot it. I would have just spent it on more remaining E100G.