Many people say "no rust" but it may be well-hidden under Bondo or underneath the body. My 78 280Z (the 240, 260 and 280 were essentially the same body, the 280 just had huge steel bumpers tacked on...and fuel injection) had pretty severe rust in the rear hatch and taillight area sheetmetal, in the front rocker panels and lower fenders, and in the driver's frame rail. I had the frame rail replaced and ground all the other rust off and covered with fiberglass and bondo, so you can't see the rust but it's still there. I'd hold out for as clean a car as you can afford. Mechanical stuff is easy and, for some, fun, to fix but body work is the realm of the true restorer in my opinion.$5500 Canadian is about $3500 USD, I'd think that car ought to be decent if it's fully worth that amount (I paid $1000 for mine with plenty of rust, I've seen worse rust on cars costing three times that). Check very carefully! Maybe take a trip down to Arizona or another arid US state and find one that's been baking all its life in the sun, some cars out there have near-pristine bodies supposedly.
[edit] here's some pics:beautiful restored 240Z for sale I saw online oncemy car a long time ago, just back from the paint shop with the large bumpers unboltedrecent pic of my car after a cheap repair to hood (deer impact)