The cost of live rock depend on how muvh you need to be honest. It certainly wont cost $200 to fill a 1 gallon tank.
I dont live in the US so i can only go by UK standards but generally the US is far far cheaper on marine things when compared to the UK.
I would say that you would be ok with 1.5kg of live rock for a tank this size. In the UK this would cost roughly £15 ($20 roughly i think)
Live rock costs about £11 per kg here. I think the US has it far cheaper but at this price it will be equal to about $17 per kg i think. If you go by the guidelines that 1kg of live rock for each gallon in the tank (and remember that a US gallon is smaller than a UK gallon) then you will have enough live rock to do the job.
Ok, now we have the live rock sorted now we must think about circulation...
A reef tank needs at least 10x the capacity of the tanks turn over per hour for circulation. (remember that reefs are not quite tranquil places, they are areas with huge powerful currents and surges that to be honest, we simply cannot replicate in this hobby. So.. for a tank with 1 gallon capacity you will need a powerhead that does 10 gallons per hour turn over rate. this will be tricky (though not a bad thing) as you will find even the smallest powerhead will turn this over without breaking a sweat! gothe the smallest powerhead to find a good flow for the tank. (not sure of prices for such a small powerhead)
Ok now we have the circulation sorted. We now need a heater. Againa small heater will do but this will need protecting as snails are likely to crawl onto the heater when its switched off, when the heater kicks in, they cannot get off the heater in time and will cook themselves

Placing the heater in a sleeve or something will be fine.
Lets talk about sand now.. i would recomend a large size grain as the turn over in a tank this size will be very high and if you get a small grain size then the tank will be forever cloudy. DO NOT put more than enough sand to simply cover the base of the tank. Sand can shelter left over food and thus it will rot under live rocks etc. you simply cannot afford to havce more than a surface scrapping of sand for a tank of this size. In fact i would suggest no sand at all and just ask you lfs for some live rock grunge. (in case you arent sure what that is, its basically all the little bits of rubble in their live rock tanks that fall off the live rock during the course of its time in the tank. Its teaming with life and usually you can get it for nothing over here) The grunge can be used as a rubble zone, this is far better envirnment for Copopods and Apmphipods, small shrimps etc prefer to live in a rubble zone over a sand zone.
Ok lets think about lighting
Now it really depends what you want to keep but i would not sugest halides as they will simply raise the temperature far too high for a tank this size. So we are left with 2 options. T8s and T5s. Although T8s are nice, i would say that you could get away with T5s (normal sized tubes) over the tank, they wont effect the temperature too much and with a 1 gallon tank its more than enough power to penetrate to the bottom of the tank.
That is about it really.. however....
If you have a large external filter you could hook this up and use that as the powerhead and of course fill it with medium for filtration. My only concern with this is the bacteria that will of course multiply inside will be using the oxygen that will be needed for the tank. However, if you can get good water movment (you should in this size tank) then i dont think it will be an issue. The advantage of having a larger external on the tank will of course increase the gallons in the tank..
Lets look at a larger example..
I have a 100 gallon (UK) with a 35 gallon (UK) tank as a sump. Even though the tank can only hold 100 gallon as far as swimming space is concerened, it actually have a water volume of 135 gallons

thus more water and more stable.
The same primciple would work for your tiny 1 gallon.. (might even make it a 3 or 4 gallon if you have a large enough filter!

)
I hope this has helped you a little and gives you a clear example as to what you need to be trying to achieve. I am still concerened about how this tiny tank will remain stable but if its kept in a cool part of the house where the temperature rarely changes then at least the temperature side of the tank will be ok. You will need ot do constant water management of course because if anything goes wrong in a tank this size you will have to work fast, REAL FAST
Lets not forget the cleanup crew...
Perhaps 2 turbo snails and a redleg or 2.
OK lastly the fish...
Clowns are going to be just too much for a tank this size i think. How about some small gobies? A catylunya Gobie or a green clown gobie would make a good addition.
This would be pushing the system to its limits to be honest but at least it gives you a framework to try and build from.
Good luck
Navarre