The Vario is really quite simple to assemble, no special tools required. Not much script, and what there is is in german anyway. Some of the photos are lacking specific detail of how every single piece goes together, but given a little thought & trial/error, it builds itself. And the savings would put you well under your limit.
And I don't care what manufacture you buy from, there will always be little problems that need be corrected during ongoing use. I'd highly reccommend that you build it yourself & then you'd have greater knowledge to diagnose the problems when they occur.
