I found out quite by accident. I had been searching for another glass top/lid for my aquarium and was price shopping online. I came upon Dr Fosters&Smith website and was pleased with their price and free shipping.
I put together a want list the following day and went back to their site to place my order. It was then that I noticed that the same item was $15.00 cheaper than it was the previous day !!! Their free shipping for orders over $19.00 is a great deal. Ive talked to them and their last day for online orders will be 2-2-2019. Every day I get an online coupon and today's was for 20% off everything including sale items.
Im going to hang in for a few more days hoping for more discounts as my want list is growing.