In store? Limits are only imposed by store managers. Some stores strictly limit to like a couple hindered dollars, others you can buy a couple thousand. Best bet is to go early in the morning and buy what you want. If the cashier stops the transaction from going through and tells you there’s a limit go back that evening and pick up the rest.
Make sure to give it a few hours and then check your gift cards to assure they activated properly.
Online.