Its pretty easy really. Get a cardboard box, and ever find a styrofoam cooler that will fit in it with a cover or make your own that will fit in the box. Bag each fish individually! That is very very important, that way they won't injure each other, and won't stress each other out. Fill the bags with just enough water for them to be able to manuver around, the bags should be about the same size wide as the fish is long. You can bag buddies to the water, releases Oxygen and helps to calm the fish, after putting the fish in, fill the bag up with preferably oxygen, but atmospheric air will work, tie it off, and then put at least another bag over the one the fish is in, preferably triple bagging is much safer. Then stand all the bags upright in the Styro, then make sure everything is tight, use newspaper to pack around the bags and help to hold them in place. You don't have to do this next step but it helps, get one of the large bags your LFS can get in when they get fish, and put the styro inside that so it won't leak all over the place if a bag does leak. You can get 25+ hr heat packs through afew sources online, prices vary, I can get you some of the better sources if you guys want, but then what you do with that is tape the heat pack to the top of the cover, and cut a very small hole in the styro cover to where the heat pack is, this will prevent things from getting too hot, but keep it warm enough for the fish. Then just finish sealing things up, tape the styro shut, then pack the box, tape everything off, add some fragile...this side up...live tropical fish...etc stickers or whatever to the box and you should be ready to go. Shipping charges are never refunded to the buyer, only the cost of the fish, or replacement of the fish with the buyer paying for the shipping charge again. Generally, most people will send an extra or two, just incase a loss does happen, its a little bit of insurance. Nothing you have to do, some people do, some don't.