If your trying to make money.. Its like everything else evaluate the risk.. Then go big or go home...
Fact is every bot you put up will make back your cost from GOLD alone in just under 30 days... Now factor in items and a bit of luck and your in the black after 2 weeks...
Note this is irregardless of how many bots you run.. 1..3...5..10.. The only thing that is going to dent your timeline is leveling.. If money isn't a problem and you don't have a main.. Than pay for powerleveling.. Either all of them or just 1 then power level yourself...
Or if you got 2-3 days run rrix's All Quest profile.. Once they reach 60 you should have about 1.5-2M in gold which is enough to budget gear a barb or wiz for MP0 where you could then pay for your own upgrades in 2-3 days where you can up the MP level....
In short, if you have the resources you can pull into the black in 2-3 weeks, otherwise your looking at 3-4 weeks...
As for profit.. Its pretty easy to pull a profit on anything in life when your only costs are startup costs...