I bid 100BTC, which means that if I win, I'll just let you keep the darn bond.
OK, to be honest, I'm really unsure how this works. You want someone to pay you now, in exchange for a payout in the future?
If you bid 100 BTC, this means you'll pay me 100 BTC at block 116,000, and I'll pay you back at block 120,000. You would lend me money at zero interest rate.