When I moved I placed an add on craigslist ( now facebook might be better). Had very low prices on corals and fish.$10.00 mated pair of clowns, ect..... Not free, as I wanted people to have some skin in the game, so they would take care of them. I had quite a few people respond that I knew had little money to buy things but had well cared for tanks. Those people were the most great full.
The tank and equipment went for about 1/2 the new price and sold quickly