You will be fine with any LR alloys...just don't forget to buy new wheel nuts too. However if you go down the second hand route make sure they are actually Boosts as a lot of Deep Dish alloys get advertised as Boosts and IMHO are not as nice.
Second hand is a good option...due to the size of tyre usually fitted, scuff marks are rare. I picked up 5 Boosts in perfect condition for £250. Totally legit too...private sale from a doctor who had fitted Sawtooths to his 110...they even came with the Sawtooth boxes. I concur that for extreme off road use steel may be better, you would really have to be going some to damage an alloy in everyday road or laning use.
I have to say though I think Freestyles really, really suit a 90, cheap as chips too. Freestles for a 90, Boosts for a 110 if you ask me.