a 25 would be considered a nano it's much harder to keep stable then a larger tank.more challenging if your a beginner.in most nano a single coral maybe 2 fishes and a shrimp is the only thing that can be kept in there (easier a bit to upkeep for beginners ) more advance reefers can do with a heavier bio load meaning more corals.
my tank if calculated in my currency would be over 2000 just for what you see in the tank skimmer,pump, canister ( filtration with sump is best for reef ). it doesn't include the cost of additives like bacter vital,snow,premium food, frozen mysis,frozen cyclops,trace element's,buffers,n-p pellets,bioptim,bio-digest,ammo and po4 controllers, water conditioners,calcium additives,a different master test kit,added mg,ca,kh, and trace testers.
and i don't use a chiller ( it cost about 650 minimum here )