I ordered skates from the Facebook ad and the skates were delivered to my door in less than 24 hours. The gentleman selling is based in Montreal and was both honest and easy to deal with.
In terms of sizing, here’s what I know: my teenager wears size 11 or 11.5 (D/standard width) Nike basketball shoes but an 8.5D Mako skate. We were fortunate in that he already had a pair of M8s that simply wore out, so sizing wasn’t an issue at all — we bought the exact same size. But in a general sense, I can’t imagine buying any new skates (Bauer, CCM, etc) without a proper fitting. For instance, prior to lucking out on the new Makos, the boy briefly wore a pair of Supreme 1S skates and they were size 7.5D. Sizing can be all over the map.
Hope this helps.