There are many ways for a magus to pay someone without paying them. Most of them will have people screaming "Magic". This one blames it on the fey...
Paid by the Faeries
Muto Herbam 35
Requisites: Terram
R:Touch, D:Moon, T:Individual
This spell changes a leaf into a gold coin for a long period of time. Then it turns back. base 4, +1 Touch, +3 Moon, +2 Gold, +1 non-plant product
Base 4, turn a plant into a metal
+1 to turn it into something other than a plant
Everyone knows that faeries pay with coins that can turn back into leaves. Sometimes these coins get passed around before they turn back - usually because of the current owner. This spell lets a magus create money to buy things with, and then be part of the innocent "victims".
If base 4 changes a leaf to metal, why do you need the +2 for gold?
Do you need +1 for the complexity of making it look like a coin rather than a small gold disc?
And yep, as Callen pointed out you only need Group if you're casting on a lot of leaves.
How fast does currency circulate in Mythic Europe? Especially large denomination currency like gold? How many places actually deal in gold currency?
Assuming you modified the spell to make silver currency, this might be interpreted as breaking the Code.
I am thinking of the Peripheral Code in Stonehenge tribunal that limits how much magically created silver can be put into circulation.
Some might argues it interferes with Mundanes, as the final recipient may find themselves suddenly very poor. And ready to raise a pogrom against the fae and anybody who looks magical. Currency is a form of trust (that it is actually worth something), break the trust with enough fake currency and trade collapses as people go back to barter.