I'll look it up on Expedia or Travelocity just for comparison, but usually buy direct from Southwest. No bag fees, no bullshit, and they fly direct from RDU to LAS. Dunno about CLT.
It's worth comparing rates from GSO vs CLT. Prices can be pretty different.
Sometimes US Air is actually cheaper starting in CGO and stopping through CLT than leaving from there directly.
Ive had best luck booking directly through the airline. Usually fly out of Charlotte because its a USAirways hub. Plus I get to rack up the miles that way. Don't fly out west often so not sure how it would compare. Most guys I know from around here that flew to Las Vegas when they held the SIA trade show out there flew out of Charlotte or Greensboro.
Kayak.com is the best comparison website. Find a ticket and book it through that airline, that way if anything changes the airline will typically fix it for free instead of paying a $50 fee to expedia/priceline for them to have it changed for free.
Its been a few years since I've flown, but the key is to get in before the 30-day cutoff. Used Orbitz.com to get an idea what the price is, flying out of either GSO/CLT/RDU, then book direct
with the airline's website. I've flown out of all 3 "local" airports, depends on the destination and airline. I've been to Vegas, probably flew out of RDU for that.