For Mother's Day weekend, the new West Coast airline "aha!" is offering fares from $39 one way. Their route coverage is pretty limited, but if you're based around any of the cities they serve, they might offer you some useful connections.
As far as we can see, their flights usually start at a minimum $75 for shorter routes, so $39 is a solid sale price if you find dates that work.
If aha! doesn't really offer the flights you want, try searching for other airlines using our flight search tool.
All of our deals are available at the time of publishing, but prices are subject to fluctuate and change at any time.