I would recommend Premium Outlook Mall - Millenia Mall is not an outlet - lovely but not if you want any bargains!

Don't think there is anywhere you can leave your shopping, but you could always try the individual shops concerned, or ask Guest Services when she asks for her discount booklet. If you are a member of the AA you get AAA discounts, if not pick up one of the discount voucher books on the 192 - they are usually in that as well.