The cheapest method by far is outdoor scaffolding for burley curing. It basically consists of a row of poles with 3 boards running along the top portion 2 on one side and one on the other side of the poles. There should be about a 1 inch gap for the tobacco stick to be stuck into the scaffold. I know that is not the best description, but there is a more detailed description at
http://www2.ca.uky.edu/agcomm/pubs/id/id116/id116.pdf
You can cover it with plastic for curing, or make a roof over it. Around here alot of folks get scrap tin from the scrapyard and make a cheap roof over the top. This system will hang the most sticks of tobacco for the least amount of construction material and by far is the fastest system for hanging tobacco especially if you build it in the edge of the tobacco field. Barns require climbing, and a sort of acrobatics in order to hang tobacco in them. Not to mention that hanging in a 3 or 4 tier barn is a real pain if you plan on doing the work by yourself, because you will have to hang a tier and then climb up and move it up another tier, until you get it in the top. You cannot hang tobacco as close on the poles in a barn as you can on a scaffold either. It will houseburn if too close on the poles. At the same rate, burley will not cure properly if you do not have a full barn, or the barn hung at a proper capacity. What makes the scaffold good, you can hang most tobacco 5 stalks to a stick and the sticks about 4 inches apart, in the scaffold, if field wilted good. AT least that is the capacity that my climate seems to uphold best for curing. It will be different in every area, and climate. It can also be hung closer together in a sunny and dry spot, than in a damp or slightly shaded area.
If you have the time and material, a barn is better for multipurposing, and you will have less sticks to fall in windy weather. Sometimes you will have some sticks of lighter weighted tobacco blow out of the scaffold, more so than in a barn- though I have had whole rungs of tobacco blown down in real windy weather even in a barn. Everything has its tradeoff. If you are sure you will grow burley for a long period of time like 20 years or something, I would go with building a curing barn. If this is more experimental or you are not sure you will grow for a long period of time- Scaffolding is best. I have seen tobacco barns 7 tiers high- you definitely DO NOT want to build one of those- trust me. Nothing but Labor, and when you quit burley- wasted/ useless barn space. In small amounts 1 tier is definitely the way to go.
By the way 2000-4000 plants will be a lot of tobacco for one family. You are looking at somewhere between .25 and .75 of an acre of tobacco based on spacing in the field, and with a good yield on that amount acreage anywhere from 600lb for .25 acre (average yeild)- 2400 lb for .75 acre (higher end yield)of tobacco. I am told that current processing at a Manufacturer would put that at 6 cartons of cigarettes to the lb of tobacco. 3600-14,400 cartons? Home processing will be much less, but still a lot.
I joke every year when I plant my tobacco, that If the markets are bad I will be chewing alot this winter.
Hope this info is of some help. I've hung alot of tobacco in my time- you will probably be very pleased with a scaffold. I wish every stick I ever hung could have been put in one, and have been properly field wilted first. I bet my left shoulder would not keep me awake at night.