Fixed odds betting allows you to lock in a specific price on a horse at the exact moment you place your wager. Unlike Tote betting, if you take the available price when striking your bet your potential payout does not fluctuate regardless of how much money is later bet on that horse unless there is a late scratching or your horse is involved in a dead heat.
Tote betting runs on a parimutuel system where all stakes are pooled together. After the house takes its commission, the total remaining pool is divided equally among the winning tickets, meaning your final odds are only determined after the race closes.