I have a Karcher which retailed for around £200. That said, mine was a snip at £60 in a charity shop. It was almost new and the steam-iron attachment hadnt even been out of the box.
Prior to that i'd been using some cheap & cheerful thing which i'd got from the catalouge. Although the Karcher has the facility to switch the steam off and on (unlike my very cheap one), i have to say that the cleaning performance was no better. I'm still not sold on the idea of steam cleaning, though it comes in handy when defrosting the freezer.