A few weeks ago a guy had a big box of them at the gun show. They were the German GECO flare guns from the 1960s. They were $40 each and he sold a bunch of them. I already have one, so I didn't exactly need another one. This is the same guy that had gorgeous K31 bayonets for $60 with sheath and frog and the K31 cleaning kits for ten bucks each. So cheap.
The parachute flares are definitely the best. They're just fun and they're longer than the other ones. The surplus flares have wax covered cardboard boxes and stripes on them depicting what's in the box. There's red rain, a single red star, single white star, and a few other ones. Buy the flares in person at a gun show. The hazmat fee for shipping flares is crazy. It doesn't pay to order them online if you can get them in person without having to pay any shipping fees or hazmat. In person, I pay $30 for regular flares and $35 per box of parachute flares. Each box has 10 flares in it. I'm trying to buy them up at each show because who knows how much longer the surplus flares are going to be available.
Be sure to rinse out your flare pistol after shooting a few flares. Its amazing what'll come out of the bore when you rinse it in the kitchen sink. Hearing protection is recommended too, its similar to shooting a 45acp.
They're not exactly coast guard approved, but I keep mine aboard my boat. What a great excuse to buy and play with flares.