handguns are a little interesting. a ffl holder can ship by uspostal priority in the fixed rate boxes. this is, by far, the cheapest method. usually 15 or 20 bucks, and insurance is cheap. you just have to find a ffl who is willing to ship by uspostal, and not charge you an arm and a leg for the paperwork. i got on gunbroker.com, and checked for your zip code, and there are a few within about 30 miles of you, charging between 15 and 20 bucks. your best bet is to talk to a few of them, and get everything arranged before you even try to sell anything. ups and fedex are both very cost-prohibitive!
long guns are a little easier. YOU can ship a long gun by postal priority. you just need to make sure that the ffl you are shipping to will accept a shipment from a non-ffl-holder!
the best thing is to do a little homework, and hit a few dealers, and come up with a ffl-holder who will be your bud, and handle your shipping! it takes some time, but i have finally found a dealer who is right next door to a post office, and charges me 10 dollars to do the paperwork, coming in or going out. he is a good guy. i buy stuff from him occasionally, and i just stop by and shoot the breeze sometimes. it makes interstate firearm transactions immensely easier!!!
good luck!