American Airlines have some round trip airfares travelling from Dallas (DFW) to Reykjavik Iceland (KEF) for $389, nonstop. This is a regular economy fare.
Travel Availability:
Departs DFW: Aug 20, 21, 22, 24; Sept 4, 5, 19, 23, 26, 29; Oct 15
Returns: good availability returns but play with dates because it changed a couple of times
Use dates and book it on Priceline or American Airlines . Priceline will give you alternate dates if they find one cheaper so try that first. Bundling hotel with airfare will save money.
http://www.priceline.c