Creating Odds f or yourself with draws

[krammatrix]

This is a concept i've been discussing with my roomate and I don't really understand. Say you have like a QJs type hand on a T42 flop with two of your suit. According to my roomate's logic, he bets and you just call, you're not getting odds to call again on the turn if you miss. What he argues is that if you cap the flop with him, then you're creating the odds for yourself to continue with the hand on the turn because you're creating a pot for yourself. What it seems to me is that you're paying to get those odds. You can pay that same 4 small bets you put in on the flop to see the whole hand, why would u put excecss money in? Sorry if this is elementary, i just dont' really get it