Even one mark is three minutes of effort just to teleport once, at that point I think I'd rather walk. That's far more expensive than any other teleport in game currently. If we considered a very modest hourly gold profit of five mil, three minutes of effort would have a teleport costing 250k.
If it has to cost marks, it should be a charge based system. I'm thinking more like ten or twenty teleports per mark. That's far more in line with the ongoing rate of teleports. Alternatively, make it a channelled cast with a neat animation. Can be instant if the quick teleport option is enabled, which will cost X quick teleport charges.