If your goal was to specifically get a ticket AMS-SFO with a stopover in Iceland, then the price is OK.

But if you just wanted a cheap flight to get home, you could have found other cheaper prices. E.g. a quick search on Itasoftware shows Norwegian available on April 9, AMS-OSL-OAK for 234 euros, with a 16 hour layover in OSL. Or you could get a LGW-OAK on several dates in April for $236. (You would have to add a separate AMS-LGW, though, but there are several cheap flights available on e.g. Easyjet.)