I have a 1.17 gallon critter keeper that i got at Pet extreme and it was like 7 bucks and i was at walmart the next day with my dad and they had the same for 3 bucks! i was mad.
I don't use gravel so I never have problems with scratches. PLus to clean them I use an algea sponge ($2 @ walmart)..which is made for use on plastic/acrylic..so then again..no scratches.