Personally, if you can provide decent lighting and control temps its not any harder than a regular larger tank. Use a larger hob type filter unit like a AC300 or 500 on it, and turn it into a refugium, some macro algae in it, and a 13 watt PC with 50/50 in it and it should be more than sufficient. You can use a smaller hob type powerfilter like an AC20 (mini) equally as well.......When you get right down to it, getting decent lights and controlling temp on large tanks can be just as difficult.........One thing that is hard at least in my area is finding small enough frags to utilize in it........You can use the Hydor mat heater in a small hob filter/fuge or lay it on the tanks bottom and cover with LS/LR and its out of sight except for cord, or install it or a smaller 25watt heater if need be in the filter fuge..........Its really not all that much of a chore, and regular partial water chages is usually more than sufficient, unless you have a decent hob filter to breakup and pickup surface scum.....The typical NANO type hob filters do not have sufficient power or flow to do the surface film dispersion, but the AC20 (Mini) has more than enough.........leave out the fish and no filter is needed, just routine water changes is sufficient.
The image I posted above is not of my tank, but that tank in the pic is available at a major pet store chain at close out prices....Retail was orginally $23.99 on clearance for $6.11, a AC 20 mini is about $21.95...........roughly 4 to 5 pounds of LR - whatever you find it for, and about 2 cups or 1 pound of sand for a sand bed is sufficient.........no deep sand bed is needed, nor recomended..........A Red Sea (Art Decor) clamp on 13 watt PC light is about $15-20 and a 50/50 bulb for it is $5.00 or so, as it comes with a daylight type bulb.......Other than that, the only extra costs will be what you put in it in regards to inverts etc........A trio of sexy shrimp does extremely well in it, or just corals, dusters etc, maybe a small cerith snail and 2 or so tiny blue leg hermits (about a buck each) and no fish, and its still much nicer than any FW setup is. YOu should easily be able to setup a pico reef tank with shrooms and common polyps for under $100 if yu had to buy everything from scratch at regular prices, or about 60% of that price if you shop around. I have seen reef tanks done pico fashion in 2 and 3 quart brandy sniffers, or a 3 quart Aqua Vase as well as a 2" x 2" x 2" acrylic cube and they all look terrific........Stay with just corals etc, and no feeding is necessary, just water changes will suffice..makes life a lot easier.