Single car sear adaptor for Baby Jogger. Description here: http://www.snugglebugz.ca/car-seat-adaptor-single-city-series.html
Paid 80$ plus tax, used from May-Dec 2013. In like-new condition, with box and instructions. 50$ p/u in pointe Claire.
the Baby Jogger website lists which car seats and which of their strollers it fits.