This is what I bought. From Wal-Mart

http://www.walmart.com/ip/Bell-Pharmaceuticals-Double-Strength-Caffeine-200-Mg-Caplets-Jet-Alert-90-Ct/14335882?action=product_interest&action_type=image&placement_id=irs_top&strategy=PWVAV&visitor_id=51201462411&category=0%3A976760%3A976798%3A1001537&client_guid=a140ad1b-fd63-44cf-9e5a-e3257dbf039e&config_id=2&parent_item_id=10403809&guid=17e4bde3-6d44-4307-8fae-3d62f601ab6e&bucket_id=ir*****ucketdefault&findingMethod=p13n

You can get it at any store, it is over the counter.