Group-stage contracts summing to less than two

Four teams play in a group from which exactly two qualify. A contract on each team pays $1$ if it qualifies and $0$ otherwise. Prices: team 1 at $0.84$, team 2 at $0.73$, team 3 at $0.25$, team 4 at $0.15$. You can buy or sell any contract and buy or sell bonds paying $1$, with zero interest. What up-front credit can you lock in with an arbitrage?

$0.03$. Holding one of every contract always pays exactly $2$, so the four prices should total $2$; they total $1.97$. Buy all four and short two bonds: you receive $2-1.97=0.03$ now, and the payoffs cancel at the end.