Headlight or Headlight lense?

[oi_oi_savaloy]

It looks like this could be a really expensive Feb - not only am I going to have to do the Cambelt (see previous post) but one of my headlight lense's has been hit by a stone or something thrown up off the road.

So.

Do I have to buy the complete unit (it's still working but the lense is cracked but still in the light) or can I buy a lense instead?

It's for the Passenger side outer dipped light.

And finally - is there a big difference between passenger and driver's lights in terms of prices?
Thanks,

Rhydian