The light of a flash is very hard, therefore many firms make wonderful flash-equipment like bouncer, diffusor, etc. for their flashes. But it's going to cost whatever it costs.
For everything there is a DIY-instruction, like these for a bouncer and for a diffusor.
So why should we spend money for it?
1. just paper (and scotch tape to fix the paper):
2. 2-in-1 bounce card (one side: white paper / other side: kitchenfoil):
3. transparent plastic (from a Fuji-35mm-filmbox):