The price of wool for commercial use is way way down. In the UK it barely pays for the shearing.
How many sheep depends on may things. It depends on how much land you have, the type of ewes you keep and the market for lamb when it comes time for killing them.
To make a living purely from sheep breeding you would need in the region of 500 ewes. Say that you had 200% in lambs and managed to get them all to kill weight, this would yield you roughly $19,000 but you would have al expenses on top of that - worming, feeding, shearing, transport to market, fencing, milk replacer for orphan lambs.
Initial outlay would be high, purchasing ewes, fencing, good rams, sheep hurdles and so on.
You will rarely ever get 200% from a lambing as sheep have a strong desire to die for no apparent reason at all.
Po Peep experience