When can one purchase and plant bare fruit trees? It is too late this year isn't it? I don't much care what the trees are. I am considering bare root to simplify a transportation problem.
Many places - at your local garden center, which should carry cultivars that will do well in your area (you don't mention where you live, that helps), as well as many places online. Some of the eastern sources may still have bare root trees available. Other resources on the west coast, like Raintree, may be out of bare root at this late date. Let is know where you live, and we might better be able to tell you where to go. Also, what bareroot fruit trees you're interested in, as there is a very wide variety option for bareroot fruit trees. And, regarding a "transportation" problem, not sure what you mean by that? Once you receive the bareroot tree, they need to be planted in the ground, thus they are not "transportable".
I second what H says as a priority....select trees that do well in your area. A little research here is valuable!
I just got off the phone with raintree.. Their last shipment to Ohio is may 12.
Hope this helps,