Er, why exactly are you buying a Fafnir weapon for 20b when the average cost of a clean weapon is typically ranging from 5m-20m (often on the lower-end of that scale)? I won't question your decision or anything, but Fafnirs are not typically worth twice the meso cap.
Also, please do not accuse others of scamming on the forums. Report them in-game or file a ticket.
1) Not everyone plays on a normal server and has access to 2x cardSniff Sniff, boo hoo. 2x event + 2x card + some for of additional drop be it spider or w/e = PLENTY of nodestones. There is little to no merit in these complaints other than MAYBE arcane River droplets. In 3 hours of grinding I got 75~100 Stones (did 3 sessions) more than plenty for a day. NEEDING more than that is pure entitlement.