One of the great things with killies is that you are able to receive and send your species to all over the world. When dealing with E.G. cichlids your are dependent to the species that are offered in your local store. Of course shipping of larger fish is also possible but it is quite expensive if you at the same time want to follow the ethic rules of animal transportation.
With annual and semi annual killies this is much much easier. You just send or receive an envelope with as small poly bag containing peat and eggs of the exact species you want. Then you wait the incubation time and start to hatch your own fish.

You can also send and receive adult killies but you have to be sure that live animal shipment is allowed with the mail service you use. Also remember the climatic issue. In the winter season it is quite difficult to send anything in the cold areas. For short distances a heating pack could be used but for longer shipments it is best to wait for proper weather conditions.
If you are going to send or receive killies a good advise is found below.

If you are not a member of a local group with fish and egg listings you will might be able to find some fish and eggs HERE and on the below links. I suggest you to buy fish which have the entire strain and collection code so you are sure that you receive a "clean strain".

If you have other good listings - then just let me know !

Advise on sending fish to increase survival chances:

1) Use strong polybags specially made for fish transport
2) Think about weather conditions in sending and receiving country
3) One fish into each polybag - and ONLY one
4) Maximum 20-25% of water in the polybag - the rest must be air.
5) Do not blow up the polybag with your mouth. Your lungs have taken much of the oxygen. Use a pump instead to add air to the polybag.
6) No feeding of fish the last 24 hours before shipment.

If you follow above steps the fish normally will not suffer the transportation and will be received in perfect shape.

Advise on sending eggs:

1) Pack peat and eggs tight in a strong polybag.
2) Mark the polybag with Genus, Species, Strain and date of harvesting the eggs. A good thing is also to mark with your name so the buyer can easily find you if he needs further advise on the eggs.
3) Pack it in a bubble envelope. This avoids damage of the eggs if the envelope is giving hard handling in the transport.
4) Think about weather conditions in sending and receiving country