The simple Teleport spell is the first -- and thus most common -- spell wizards gain that whould allow him to cross distances suitable for a trading venture. Unfortunatly, the spell also has two severe disadvantages.
The first such disadvantage is that the spell is not completely reliable. Even a wizard intimately familiar with his destination takes a risk that the spell will malfunction. The spell has been known to go "off target" and send the wizard somewhere "near" his destination or even to a place that might be nowhere near his destination, but which closely resembles it. Worse for the aspiring merchant-mage is the fact that the error for being "off target" is proportional to the distance between the point of departure and the desired destination. Thats a definate disadvantage for someone seeking to bypass long distance trade routes.
The other disadvantage to the spell is that it transports the caster instantaneously with whatever he can carry. This rather severe weight limit prevents the wizard from engaging in any sort of bulk trade. Even the use of strength spells and extradimensional storage devices such as Bags of Holding will not begin to approach the carrying capacity of a cargo ship or a trade caravan.
It is still be possible for a wizard to engage in trade in high value, low bulk luxury goods if he wishes to take the risk of error every time he uses the spell. Indeed, there are those who have been known to trade in gems, spices and other luxury goods in this way, but those willing to do so are few.
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