[ArtVandelay]

Preflop I really dislike your raise. As hard as AK is to play in limit, it's even worse in big bet, especially for new players. The problem is that raising small here opens you up to a reraise from the first raiser while gaining you little in return. Should the original raiser have AA he will almost certainly put in a big raise when it gets back to him, and if he puts in a big raise anyway with QQ, AKo, or something else then you'll probably have to fold a hand you would have liked to seen a flop with. If you're going to raise at all with AKs, I recommend a much bigger raise putting real pressure on the original raiser, because you're basically happy to win the pot right there. However on net I think a call is best, because you do want more players with a hand like AKs, and because the raiser has 100 left you will have to give up if he comes over the top no matter how much you raised (unless you foolishly pushed all-in yourself).

So presumably now there's 25 in the pot for 5 way action on the flop. On the flop I think your call is the right play. Some people would suggest pushing all-in, but given that the pre-flop raiser has 100 left you'd basically be getting 6:5 odds when he calls. This is the right price if he holds KK, QQ, JJ, AT, or KT, and you lose a little when he holds AA. If he has a set it's bad though. The real thing is, I think you make more by calling. He will only have one pot-bet left for the turn, and if he is like a typical low limit big bet player I imagine he'll commit the rest of his money on a small club. So why push now when instead, by calling and waiting for the turn as you did, you can get all the money in when you're virtually a lock and get away from the hand if you miss. The one disadvantage is that you will lose those times you would have flushed on the river, but from an E.V. point of view I suspect calling is slightly the better play. The key is that you think you'll get callers behind, which you love, who probably would fold for a push. This additional consideration I believe makes the decision a clear call.

On the turn the pot is 85, the raiser has 85 in his stack, and the player behind you has about 25 left (according to your other post). To simplify we'll pretend the guy behind you always folds, which probably makes a call less attractive because any hand you make will almsot certainly beat him. Raising all-in is actually a possibility here, because (assuming you'll always be called) you're getting 2-1 odds one conceivably 18 outs. However, that's a best case scenario, and I suspect in general you are drawing to about 12 outs, which makes a push wrong. The E.V. of folding is 0, which will be our baseline, so let's analyze calling.

We'll assume that on the river he always bets all-in. This is probably fine because if he checks it will usually be because a scare card hit, which makes your hand, and then you'll push all-in and he'll almost certainly call with the odds he'll be getting. Anyway, the question is which river cards do you call and which do you fold. Clearly if the flush or a jack hits you call, and if any non-flush card below a king hits you'll fold. The question is do you call when a king hits and do you call when an ace hits (they're different because the king makes a 4-card straight, for example). To do a full analysis I'd have to know what sort of hands are consistant with your opponents play, but again to simplify we'll assume he plays AA, KK, QQ, JJ, TT, 99, and AQ this way and nothing else (this seems sort of reasonable). When an ace comes you are beating KK and JJ only, and the number of combinations of hands are 1, 3, 3, 6, 3, 3, and 6 respectively, meaning you are 9/25 to be ahead, so you should call when the ace hits getting 215:35 odds. When a king hits you are beating AQ only, and now the number of combinations of hands are 3, 1, 3, 6, 3, 3, and 9, meaining you are winning 9/28 and again have a call. So... we'll assume that when you call you plan to call any club, ace, king, or jack and fold otherwise. Now for each hand your opponent could have let's see what your E.V. of calling is. For each hand we'll count how often you hit and win, how often you hit and lose, how often you fold in that order, the number of combinations of each hand, and finally your total E.V.:

AA: 12, 4, 28, 3, +6.8
KK: 15, 1, 28, 3, +24.2
QcQx: 10, 7, 27, 2, -5.6
QxQx, TT, 99: 10, 8, 26, 7, -6.4
JJ: 13, 3, 28, 6, +12.6
AxQc: 14, 2, 28, 3, +18.4
AxQx: 15, 2, 27, 6, +23.4

So, finally, your total E.V. on the hand is simply your E.V. against each individual hand weighted by the number of combinations of that hand, i.e.:

(3(6.8) + 3(24.2) + 2(-5.6) + 7(-6.4) + 6(12.6) + 3(18.4) + 6(23.4))/(3+3+2+7+6+3+6) = $10.3.

So you made about 10 bucks with that call. However, note that a lot of the E.V. came from AQ, so if your opponent would not raise pre-flop or would check the flop with AQ then things look worse, but really between aces and kings you're probably making enough to compensate for the times he has a set. The one thing I would like to say though, is that his 50 bet on the turn is mighty suspicious. He has only the pot left in his stack anyway, so why not just push all-in? To me the underbet smells like a big hands going for action, like a set or maybe KJ. If I'm right and he would push with AA, KK, or AQ then you actually should have folded, and you lost about 5 to 6 dollars with your call.

I realize this was a rather tedious analysis, but in theory this is the thing you should be doing every time you make a decision... determine the E.V. of your proposed line of play against each possible holding your opponent could have, then take this average E.V. weighted by the number of combinations of each possible hand. Hope this was at least somewhat helpful.