Best Use of $100 x2 UA Vouchers?

I have 2-$100 United vouchers for travel. They cannot be combined. They expire soon and I am looking for a way to use them. Any advise for a trip from DFW that won't cost much out of pocket. I can either book for 2 people (RT) or 1 person (2 - OWs).

I can't find a low fare finder site that will let me filter by airline.