Freshwater, no need for a sump or high output lighting, also no need for any reactors or skimmers. These things are for marine tanks and are not cheap. There are so many differences. The cost difference can be in the thousands. It rises with the size tank you get. Fresh water, gravel. Saltwater, sand. For a large tank you may spend hundreds just on sand. Then there's rock. LFS here charge $5/LB for live rock.. hundreds can be spent on live rock for a marine tank. Skimmers can run you from $150-300 or more and sumps, depending on what you get, can range from a cheap kit to a $1000 custom sump. Nothing is cheap in the marine hobby. Return pumps, powerheads, test kits, refractometer, salt, reactors, media, hell the tank itself is more expensive because it's usually drilled. Don't forget about that HO lighting that can run you from $300-1300 it all adds up plus yeah the fish are alot more $$$$ and then there's coral.