She just opened up pre-orders this morning for everything over on her website (Pony Orders) The best (and cheapest) way to get these pins is in bulk, which is the whole point of this system!
Pins will be $2 each, and shipping will depend on your location. It will take 3 weeks to a month to get the pins from the company once they have been ordered.
And a quote from Kanamai about the Rainbow Dash Pins:
"The Rainbow Dash pins that were ordered a couple weeks ago will be arriving in the mail either on the 18th or 19th. I will be shipping a large batch of pins on the 21st. So if you ordered one of these you should get a shipping notice this week. Pictures of the Rainbow Dash pins will be posted as soon as I get them."Anyway, the link to the pre-order page is below!
Pony Pin Pre-orders