A non-restricted fully refundable ticket is usually a full-fare ticket which can easily cost two or three more than a heavily discounted restricted ticket. There sometimes can be many different fares offered and are designated by fare class (not cabin-class). You might be better off booking a ticket that can be changed for a fee, you'll have to check with the airline to find out which tickets can be changed for the least amount of money, it normally would be cheaper than buying a full-fare fully refundable ticket. This applies to 1st and business class as well, just because you buy a 1st or business class ticket doesn't mean it's any more refundable than an economy class ticket, the same fare class rules apply for all cabin classes of travel.
A refundable ticket is one that you pay full price for. It is expensive. First and business class tickets are also refundable but they are very expensive.
If Southwest flies from your airport to your destination, they will not give a refund but will hold your money to buy another ticket for up to a year. That is the best policy, I think.
All above answer has nothing to do with your question.
If you have no problem with the price of the ticket, so be it and go to a reputable travel agency in your town and buy it from them. Won't be more expensive than any online agencies nor airlines directly.
Tbug is correct. Refundable tix are the most expensive. Go on line to the airport to find which airlines fly into where you are going. Call the airlines directly to find out the refund policy. Southwest, airtran, ata, and others will issue a credit to be used within a year. Good Luck