Got it. Thanks for the links, now I understood the concept well. In fact we have been doing this kind of betting in place I work in where the prize pool would be the loser's money.
I just didn't know there's a name and a whole concept behind it. So this explains why the odds keep on changing since the people are actively placing their bets on different ranges.
Parimutual betting actually has one thing that could be fine for the person who complained about the changing of the odds as well. Thequin (as always) is right about the fact that odds change depending on the person who gambles and how much money is gambled, so in the end you could see 50x odds for something at start but then everyone could wager on that for some reason and drop it to 1.5x odds, it is possible (unlikely for something to drop from 50x to 1.5x but "possible").
However there is also weighted period as well, not really entirely sure what it is called but we all know and thequin can explain better that if you wager at 50x but the odds drop to 1.5x instead, you still get more money than someone who wagered directly at 1.5x hence when you bet does play a role. Maybe you do not get that much, but you do get different returns.
Yeah I read that part on freebitco.in earlier. The weighted bonus (known as Time Weight Multiplier on freebitco.in) is what changes the game here. It's quite simple though.
Assume that person A is betting an amount $10 at the odds of 50x and the weighted price is 20x.
Person B is betting an amount $10 at the odds of 1.5x and the weighted price is 0 and the betting period is over.
Now if they win then person B will get $15 (10 x 1.5 = 15)
But the person A will get $18 (10 x 1.5 = 15 x 1.2 = 18)
So that's how the weighted price plays an advantage to person betting first.