Group buys can seriously save you tons of money. Many online shops now make it extremely easy to set up a group buy. Simply email the store before announcing the group buy, then share the discounts with your aquarium keeping buddies. The the opportunity to stock up on commonly used items such as RO/DI filters, frag plugs, and tank additives. For heavy items like salt, try gathering some friends and then calling your LFS since shipping rates are a killer. Reefing is expensive, so saving every little bit helps. Gather a few friends and start saving some money today.