If you are generating a Beecode using your Beecoins / BRP to gift someone, then there is no buying limit. If you are redeeming any Beecode while you purchasing any product / services, there is a usage restriction as one Beecode per account right now. Company will announce if there are any changes in the future which may happen.
Also, Your BeeCoin selling Limit on the BeeCoin Internal Exchange platform will vary depends on your BeeCoin Usage. Your BeeCoin selling limit will automatically come down according to your BeeCoin usage in other areas of the BeeCoin Platform which includes the Package Beecodes purchase.