Reef Cleaner Packs!
I have heard a lot of positive feedbacks on this website:
http://www.reefcleaners.org
Find Snails, crabs, hermit crabs, starfish, urchins, macro algae, anything that helps keep your aquarium’s waste level down, and glass (relatively) clear of algae.
I think with the prices they have, you can easily spend 3 or 4 times the amount on the same pack of critters! If you have a large enough tank, it’s definitely worth the while to order a large package from them. Shipping if free if your order is larger than $175. So a group buy will always be nice to help eliminate this cost!