If you want to try your hand at epoxy modelling, but are afraid of making mistakes (with expensive putty), try experimenting with Play-doh until you have your skill honed.
In the states, Play-doh is cheap (US$2.00 for 20 ounces). And, when you're finished, just wad up the play-doh and stuff it back in the container.
I've been doing this of late. A drawback is the Play-doh doesn't stick well to the klickie, so it's a little hard to model a face (I was trying to give a klickie a pig's snout and ears).
But, it's good training (I think) for working the clay.
