Anthouse.es is a very reliable source. They usually sell for educational purposes that's why their ants are so cheap (they also only have species that are native in their area, they don't sell any exotic ants). Also note that they often send 2 colonies (when you order 1), so be prepared for that to happen
Messor barbarus is a great species but be aware that they can be a bit difficult sometimes. They grow quite fast and when they have reached a certain colony size they will start to completely smash your decorations. These ants LOVE to dig, build and generally modify their environment as much as possible. They can carve out bottom substrate, cut up artificial plants, make gardens (they even water seeds that are germinating), combine different materials to build tunnels and hills, chew through ytong/plaster/gypsum/hydrostone, move even heavy objects, completely unroot and move plants, they're really really good at making feeders leak and sometimes they even chew on vinyl tubing (and if the vinyl tubing is too thin they can cut holes in it).
Edited by Serafine, March 2 2018 - 10:52 AM.