If you just need to get between Charlotte and Phoenix and can put up with basic economy, United is selling $107 roundtrip fares in both directions for Tuesday and Saturday departures. Unfortunately the fee to upgrade these fares to main cabin is really steep at over $300 bringing the cheapest main cabin fares to $413 roundtrip with United. Stick to Delta for Main Cabin fares at $295 roundtrip.
UA - CLT to PHX (or PHX-CLT) for $107 roundtrip Basic Economy
https://www.google.com/flights/#sear...932;a=-F9;eo=e
https://www.google.com/flights/#sear...962;a=-F9;eo=e