I'll admit I'm not super knowledgeable on the inner workings and operations of groups like the Bolsheviks, but before revolutions how did the professional revolutionaries necessary to lead the party, whether it be Stalin or Deng Xiaoping, get money to live? Whether organizing within the country or living in exile, they still need to eat and pay for things. What financially allows professional revolutionaries to make revolution their profession, so they can devote their time and energy fully to the cause without having to work a day job? The necessity of such a day job is what typically stops many from being able to become professional revolutionaries, as there are no doubt many Lenins and Sankaras in the world who aren't able to change the world due to their necessity to have to work a job in order to live and survive.
How can modern organizations and parties implement structures to facilite a class of professional revolutionaries?
Lenin lived mostly from his writing to newspapers. He also given some legal advice, since he was a lawyer, though i can't imagine it was anything significant since he mostly did that for free for workers, peasants and fellow communists who asked him. In harder times he often got help from his mother and sisters. Worth noting is he was personally very pedantic and responsible with finances, and this carried out to the time he was the leader of party and the state.