Several Avanti bikes have come my way, over the years. Norco is a Canadian brand. The Avanti is an entry level model. Depending on location and if I were buying, the value would be between $100.00 and $200.00 US (assuming the bike is in really good condition, cosmetically and mechanically).
But what will it cost to properly prepare the bike to make it road worthy and safe to ride? Figure on another hundred bucks, or so, more if you cannot do the work yourself.
Even if the bike is in great shape, at the very least, one should open up the bottom bracket housing, head set cavity and wheel hubs. Grease each properly and assemble. Why? Cause grease, particularly in bottom brackets, has a tendency to loose some, if not all, of its lubricating capacity. Just ask this little fellow or fellowette , who took up residence in an early eighties Nishiki Rally - he or she knows...
Too that add the cost of perishable items, such as tires and brake blocks. Both can harden with the passing of time as the environment acts upon the rubber compounds. Tires are costly items and brake pads, not so much. I strongly recommend against using old tires, even if they look really good. Had a NOS set self destruct a few years back. Even had one or two part company with air containment, suddenly. Lucky this did not happen on the front of my first PX10...
Hope that is a help.