Uh, what's that all about from Steinerb??? 
Well anyhoo....here's my 2 cents..
Paying $300. for a yearling pair is not that unusual.
Kind of the going rate for decent birds but it's all very subjective.
While $300. for a pair might seem like a lot of money to pay for some people
keep in mind that does not mean these birds are going to be healthy, in good condition
or outstanding type and feather wise, nor that they will produce outstanding offspring.
Even champion stock can produce crap offspring.
If you just want some pets you could probably get some cheaper than that,
like for $50. - $100. each for pet quality.
Don't let the breeder's title sway you.
While this person might be Mr./Ms. Wonderful just because somebody is a Master Breeder
does not mean they're an ethical seller. Ask the seller 100 questions.
That in itself will weed out the people you shouldn't buy from. Ask for photos of the birds for sale
and their parents. What good is a photo of the seller's breeding stock they aren't selling?
If they say their camera is broken or they're too busy to take pictures or the birds are in poor
condition because it's been rainy, snowy, windy or muddy outside Caveat Emptor!
NEVER trust anybody's word and NEVER buy sight unseen.