very, very few dates!
Icelandair, a low-cost Icelandic air carrier have round trip airfares travelling from Washington DC (IAD) to Oslo Norway (OSL) for $309, making 1 stop in Iceland. A longer stayover in Iceland is an option at no additional charge. Your airfare includes a carry-on bag.
Departs IAD: Oct 24, 31; Nov 28; Dec 5
Returns: Oct 31; Nov 1-3, 7-9, 14-17, 21-23, 28-30; Dec 1, 5-7, 12-15
Use dates and book it on Expedia [expedia.com]
. Bundling hotel with airfare will save money.
Icelandair's baggage information [icelandair.com]
. Learn more about the Icelandair Stopover program [icelandair.com]