For items that can be bought through say beast tribes, I can understand charging a premium. But for items that you can buy from the vendor without any extra unlocks or whatnot, selling an item you can normally buy for say 6,000g and charging 20,000g in the marketboard... it seems pretty exploitative to me. Like I said in the first post, I've seen this happen in my server mostly to housing items - which can be easily mistaken for craftable items. It's pretty sad.

Speaking of helpful websites, I really like how gamerescape in particular presents the information. They use icons right next to the item name which you can hover on to tell you whether you can get an item via a vendor, through airships, etc. If we had a similar feature in the game, that would be super helpful. FFXIV does have the Lodestone where the vendors for each item are listed; the developers could program the icon/tooltip to pull the information from there.