haha yeah I know exactly how that is. Go in for some flake food and leave with a $300 hole in your pocket and another tanks worth of fish.
Shrimp are fine to take along this way as well but I would definitely add some foliage to the bag for them.
Fish are also fine to take a long but I wouldn't put more than a few per bag.
Keep in mind fish commonly get shipped over a 24 hour period while snails and shrimp average a 2 day shipping time.