Any mention of Western Union or Nigeria or United Kingdom or other foreign lands in a local internet ad is a sure sign it's a scam and you should run for the hills.
Deal locally and always go with your gut if you feel the least bit uneasy about a transaction online - especially on Craigslist where people have ended up dead for not following this advice.
It's just a scam and you would probably find out that the house is listed for sale and that the information was taken from the internet and posted by a bogus party.
Good luck on finding a rental in the Greater Greenville area! We are called constantly wanting to know if our houses for sale will rent. Our rentals are filling up fast.
Hope this helps.
The owner is probably a seller - most of these scams are based on pulling active listing photos, then creating a fake rental listing from there on Craig's or postlets, etc.
Trulia picks up on the "posting" because they aggregate data from many sources, and you are my second experience with this scam, this week...in Atlanta, a 31st floor penthouse listed for $1.75 M was posted as an $1800 rental.
If it seems too good to be true, it probably is...my Greenville Daddy taught me that!