Fury said last month he was "over" boxing but has since changed his tune, saying he would take on Joshua provided his terms were met.
"The fight has got to be for free," Fury said in an Instagram post.
"Free to air on television and all tickets go for free. No money is to be made off of this British, historic fight if it happens," he said.
"There's the terms, I'm in the driving seat, take it or effing leave it."
