Best Buy gift cards itunes lied law Saginaw, Michigan

A little background first.  My husband and I like to buy a lot of iTunes gift cards when they are on sale at various stores.  Sometimes Best Buy offers a discount on their iTunes cards.  Recently, they have put a limit of five cards per customer on their advertisements.  When that change occurred, my husband and I would each buy five cards, as per their policy.

I went to Best Buy the other day with five iTunes cards in hand.  The cashier recognized me, and proceeded to tell me that she can only sell me five gift cards per person per day due to Federal law.  I have heard of no such law, and after searching the internet, I still can find no truth behind this.  I believe that someone higher up didn't like us buying so many iTunes cards while they were on sale, so they told this employee to lie to me the next time they saw me.  Of course, this lie was unnecessary since I only had five gift cards in my hand.  I changed my behavior as soon as they started printing a limit in their ad.

I understand that it is the store's discretion to allow me to purchase one, five, one-hundred, or zero gift cards.  I simply believe it to be bad business to lie to your customers to get them to comply.

I am not a lawyer, so I do not know all the laws of the land.  If anyone can help me find truth in what the employee said to me, I will gladly remove this report.  In the meantime, I will continue to believe that I was most likely lied to.