You can get them here:
Depends on which part of the world you are in :)
Where to buy in the USA. Seems like there should be more choices of different props.
I guess these seem like the main sizes for the copters, have you a "special" size in mind?
I made a quad with high kv motors. It works fine with the 10x4.5 props but I wonder how it would work with 10x3 props.
The point is that it's hard to find sets of both-handed props in most sizes. 10x4.5 and 12x4.5 seem to the only ones widely available, 10x4.7 props exist too but are not that easy to find (or cheap!).
Or from inside Germany: www.lipoly.de
I use them a lot and they are cheap and very fast.