When I had my mini-crash a couple of weeks ago my arm started to get a bit blotchy later that day and I was worried that I might have picked up some poison oak, so I went to Walgreens to buy a tube of Zanfel.

The Walgreen's store brand - they call it "Poison Ivy Wash"- has the same active ingredients as Zanfel but cost $20 instead of $40.

(Either the store-brand Zanfel worked great, or it wasn't poison oak after all, since the blotching went away quickly and it never became itchy)