For anyone who has a petland discounts near them, they stock up to 90g in store and usually have 2-3 1$ per gallon events. Even though they stock 90 gal tanks the usually have a disclaimer going up to 75 gal only. more often then not if you ***** enough they will bend and sell you a 90 at that price. As far as dates are concerned I'm at a lack of wisdom there. the big one is usually from black friday through new years sometimes longer.