To be the seller in this situation would be problematic because it would involve using an unjustifiable sleight-of-tongue (so to speak, she punned) to sell a relic. The seller may say that the relic inside is a gift, but he’s not going to give you this “free gift” unless you buy the reliquary. And, the reliquary is not even the main “draw” of the sale; the main “draw” is the relic itself. Offering a “bonus” for buying a product is a perfectly legitimate marketing strategy when both the product and the bonus are items that can be licitly sold. That does not apply to relics.
Does this mean that you should not buy the reliquary, knowing that you’ll be given the relic inside as a “gift”? Ordinarily, that would be the prudent course because sales encourage the sellers while lack of sales discourage them. Keep in mind also that any relic you obtained in this manner would very likely have to be authenticated before it could be used by your godmother’s community for public veneration. It may well be prohibitively expensive for them to verify the documentation and the relic itself, thus wasting the time and money you put into this venture.
I can only give you some guidelines to keep in mind here; if you need further help in discerning the proper course of action, I recommend talking to a balanced and orthodox priest or spiritual director.
