It's funny that she is complaining about $3.50 for custom cupcakes. Those gumpaste babies sell for upwards of $7.00 each on etsy and that is just plain babies with no clothing. So why should you give them to her for free basically?...
I think you are on the right track. I don't think samples to local businesses is a bad idea. Also, finf out when there will be a bridal expo in your area and do some networking there. Good luck.
I honestly think that you can offer a gift certificate for a cake of similar value at a later date, subject to availabilty. They have already paid for the cake and your time. It would be considered a kindness on your part and you're not...