I just found a company by the name of C. H. Robinson that has an internet site ......freightquote.com and you just fill in all the size and weight details and they give you a quote from about 8 or 10 trucking firms, including FedEx and UPS. It's only when you get into the larger sizes of signs (like 4 to 5 feet in diameter and 30+ pounds) that you evidently have to go "freight" which is more expensive.
I'm a little leery of Craigslist and EBay. I've heard horror stories about both of them. Let's face it, there is potential for problems with just about every selling service.........except Old Gas!