I know it makes sense to try something small in case you fail it wont be as much, but again 97% of beginners want a small tank, 96% of them fail.

The problem with picos like you listed is no fish can live in there, also you need to be an expert for a reef tank and even more so for a nano tank because corals are so sensitive to water parameters.

Water parameters will change drastically in a small tank than larger which is why beginners need to start with at least 55 gallons.

It is hard for experts to keep a pico, let alone beginners who dont understand the basic water parameters and the more advanced water parameters such as calcium, magnesium, strontium, iodine, carbonate alkanlinty.

Generally you will need more money than that. A simple 10 gallon is 12 at the petstore, for saltwater it can easily be 400-500 dollars fully set up.

The problem with saltwater and nano/pico is again water is affected more in small volumes than in large volumes.

A 3 gallon 10 gallon, even 20 gallon will need daily maintance because the water will change on a daily bases.

For the 3 gallon you will need to check the levels twice aday, add more saltwater or freshwater depending on what it reads.

What im telling you is not to do it. You really need to do this right and start with at least 55 gallons. Im not kidding how soo many people fail because they rush into this which is why it is best to research. But nano and pico aquariums are not for beginners.