Is it really true that Orthodox Prosphora (unconsecrated, of course) can not be sold or bought? I like to buy and eat protestant/catholic altar bread sometimes. It is those small, round-shaped hosts of unleavened wheat bread, they are sold in our local protestant book-shop in package of 100 hosts (with price tag around 1.25$). Usually I eat whole package at once, it is very tasty.
I am now looking for Prosphora bread to buy and taste in the similar manner. I have found so many web pages with recipes, there are lot of prosphora stamps for sale on ebay and Amazon and any other place. But I have not found any single webpage which would offer Prosphora for sale!
Is it really prohibited to sell and buy Prosphora? Generally - there are no such rules for protestant and catholic altar bread which is not consecrated. I understand that it may be a bit more tricky with Prosphora, because is is (more or less strictly) required to use holy water for baking. But anyway - quasi-Prospohra (baked with the usual water instead of holy water) is definitely the good without any meaningful restrictions, but I can not find them either.
So - why Prosphora is not available for sale or any other transaction (e.g. against donation)?
No, prosphora is not intended to be bought or sold! Prosphora is an offering, prayerfully baked by a parishoner, never for pay. Part of the bread becomes the Body and Blood of Jesus Christ in Holy Communion, and part of the bread is set aside for antidoron and distributed after Divine Liturgy. Sometimes some of this bread is taken home and eaten by those who offered it.

How should prosphora be eaten?
Prosphora  is  blessed  bread  and  should  be  handled  and  eaten  with  due reverence.  Those eating it should take care not to drop crumbs on the floor, and the paper in which it was wrapped should be burned rather than thrown in the rubbish.  Any crumbs that fall should be collected and either eaten or burned  with  the  paper.    Children  eating  prosphora  should  be  carefully supervised.  From ancient times it has been the custom to eat prosphora on an  empty  stomach,  often  with  Holy  Water  or,  if  appropriate,  a  little  sweet red wine.
Who may take the wrapped prosphora at the end of the service?
The  wrapped  prosphora  may  be  taken  by  those  who  offered  them.    When this has been done, any prosphora left over may be taken by those who wish to have them.

(Link to source, Saint Panteleimon Russian Orthodox Church, West Gosford, and Saint Nicholas Russian Orthodox Church, Wallsend, Australia)