There are three non-movie tie-in figures currently widely available from toy manufacturers.
First, from Safari Ltd., probably my favorite of all such small pieces :
Next, from CollectA, a representation of the most famous of all centaurs, Chiron:
And, finally, from the French company, Papo, this spear throwing centaur:
Hopefully, sometime in the near future the German figure producing company, Schleich, will get around to creating a centaur figure, too.
All of these figures are relatively easy to find and purchase online.
Happy taur hunting!