30% of monthly income goes to living expenses. I work for a living.
Yes, agreed. Responsible financial decisions, budgeting and saving help a lot.
This can be an expensive hobby, but then so can tennis. It can also be fairly inexpensive. For example, several months ago, I purchased a full 65 Gallon system, with sump, pluming, pumps, powerheads, liverock, soft and lps corals, four fish, skimmer, and sand, all for about $500. Granted that is more expensive than a simple goldfish or guppy aquarium, but it is far more complex.
So, since I am not quite done rambling, shall we see how inexpensive we can actually make a saltwater aquarium...
20 Gallon tank: $20 (used, easy to find, probably comes with a simple light)
Water - 5 x 5 Gallon jugs of RODI (not including jug deposit), $5 each: $25
HOB filter (assuming your used 20 gallon did not come with one): $20 new (mainly for some flow, aeration, and extra rubble filtration)
Live sand: $25 (I could not find a small bag of sand)
Dry rock: $20
Salt (Instant Ocean 50 Gallon): $16
Heater - 50W: $10
So there you have it. This basic tank totals a $146 startup plus livestock and food. Did I miss anything? I would imagine for $20, one could get a whole 20 gallon aquarium with the HOB, heater, light from an old generic freshwater kit. Either way, this will get you a system which will host a couple clowns. From there, it is a matter of adding on whatever you want to build it out.