well if you can forego fish and want cheap and simple...
deco art/red sea candy aquavase XL... 1 gallon reef tank... AWESOME!!!... they're like 40bucks, 7x7x7 plastic cube with hob filter and 7w 7200k light... I grew zoas, rics, and a branching hammer under it...
so simple and so relaxing, but doesn't have any fish...
so think...here's the price list break down:
$27 for tank and light... where the pets go...or die... also saw it online for just the tank $6.75 there's also the aquavase cradle bowl which is slightly larger.
$10 or less for big polyfilter square that you can cut up and replace the stock media (pull for 24hours after feeding)
$20 for 20w 50/50 coralife spiral CFL (not 100% necessary, but would look way better)
$20 for desklamp or free...
stick on heater $10 (may actually not need...)
live rock... $2-$5bucks...
live sand $5 or free...
then add a couple very small cerith snails, 3 astreas, zoas, rics, feather duster, an acan or something similar...
I fed mine kent microvert... like 2 drops a week, changed 3cups of water a week... topped it up twice a day, you could always figure out somesort of top up method if you needed too... just a thought if you're looking for cheap, small, and very easy. Oh yeah.. I used a hard bristled toothbrush to clean the plastic walls...