Great that you have been invited to do this. I am thinking/planning on doing this but off my own bat.
Thoughts about pricing - you have your base cost including any shipping, then as they are insisting on consignment stocks are they insisting on setting the price if not what cut as a figure or percentage are they aksing for? Then you need to add your margin.
In other words the sell price must account for your costs, "their" cut and your profit - no one can tell you what price to set because we do not have and IMHO do not expect to be privy to those details but I suggest you aim for minimum of 55% margin but if the market will bear it 70% plus for you i.e. profit after your costs and the shops cut. Having said that will 55% be enough to justify the effort involved.
A good clue as to what the market will bear is are there similar products and if so at what price ~ then if you are going to price at the same level work the price back and see what your profit will be?
Lastly, consignment stock issues. When will you get paid and under what terms of payment? Also, does the shop care for the stock i.e. how much piflering happens to the cards and how much gest damaged by poor customer handling both equal losses to you. That is why you need to make a good profit to cover such losses and still have $$$ in the pocket.
HTH 