Best approach is to look for areas where credit cards are not widely used instead of trying to displace them in areas where they work really (really, really) well.
But why would want to pay $3? Big payments are usually pretty well-timed and don't need to be "instant."
Hmmm, not sure where Dwolla is going with this, it seems to make more sense to laser focus on those who would find the most use for their product (big ticket buyers and sellers, not people buying a t-shirt on a whim).
Does that/can that happen?
However, some merchants could accept _only_ dwolla, which could change the game.
Dwolla is awesome for merchants and neutral for consumers.
I don't see why my average (online) customer is going to pay $3/mo for this, but then I am probably the only place they are using Dwolla. Also, I am very hands on with them and just take "their word" or fill an order when I get the notice that the 2-3 day travel of funds from their bank to Dwolla is good.
Again, I think this Instant thing all ties back to the CU Exchange feature I discussed before. Dwolla tries to forge a sort of deal where this bank's customers get Instant without the $3/mo fee and Dwolla + the bank chop the other half of money made in "transit time interest".
Long term, I see the success of Instant tied to this, banks being able to offer free Instant as a perk with an account with them, versus Instant used as a cheaper overdraft or standalone feature.