Comments re consumer bags at POS
The stamped/fancy bags are lovely and can double as further advertising esp if it is distinctive enough, but they do not necessarily add to the point of sales. So you need to consider the time and cost of such and weigh it against your potential market. I haven't done this at all, but if I were to market my cards at a home party or at an upmarket venue then I would consider that it might be advantageous.
Personally I prefer to reuse plastic bags as a conscience decision for the environment recycling benefits.
BTW I once had a section reserved for recycled cards for such people who prefer not to buy new and it went rather well considering 95% of my stuff is 'new' cards... maybe I should look into it but my creative heart is just not in it! Again consider your market clientele.