Just to give you an idea about a 55g sw tank. I have had my tank for a couple months. I bought the tank and stand for 100 from someone on craigslist. I bought an ro/di machine for 75 from someone on e-bay. I bought a reef octopus bh-100 hob protein skimmer it's working great so far only had if for about 2 weeks. that was 130 shipped off e-bay as well. The filter I have is Marineland emperor 400 HOB style as well. I got it for $60 at petco. It comes with 4 compartments. 2 have filter media and 2 were empty so I put in active carbon to help keep the water clear. It's rated for 90g it's working great for me since I have the protein skimmer too but when getting a filter you want to make sure it can handle double the size of the tank so the aquaclear 110 would be perfect. I jumped the gun on that one, so don't do that, but I haven't had any issues. Invest in a good test kit. The one I have and like is API saltwater test kit. It's on amazon for 20$ right now, mine was $40 at petco. The live rock i got from petco/craigslist I have about 50lbs in the tank and 30lbs or so extra thats not live anymore just didnt have room in my tank. 2 powerheads $30 ea from petco, online pricing is best from what i've noticed. the sand was live sand in bags from petco i believe it was 26$ for ea bag I needed 3. I do not have a sump, but wish I did one to begin with because I have the filter and skimmer hanging on the back of my tank when it could be hidden, but honestly it doesnt look bad. The lights are the most expensive but I was able to find 4 bulb t5 HO w/ 8 LEDS for 102 shipped, off ebay. I love the set up so far, I wish I would of gotten a bigger tank and done a sump. thats my advice i hope it helps to give you a breakdown on pricing and stuff.