Value bet this river?

[redrooski24]

I think a bet here is marginal but i made it anyway, comments on this and other streets?

PokerStars 3/6 Hold'em (9 handed) converter

Preflop: Hero is CO with A[img]/images/graemlins/spade.gif[/img], 6[img]/images/graemlins/spade.gif[/img]. Hero posts a blind of $3.
<font color="#666666">2 folds</font>, <font color="#CC3333">MP1 raises</font>, <font color="#666666">2 folds</font>, Hero (poster) calls, <font color="#666666">3 folds</font>.

Flop: (5.33 SB) 2[img]/images/graemlins/heart.gif[/img], 6[img]/images/graemlins/heart.gif[/img], 4[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">MP1 bets</font>, <font color="#CC3333">Hero raises</font>, <font color="#CC3333">MP1 3-bets</font>, Hero calls.

Turn: (5.66 BB) A[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">MP1 bets</font>, Hero calls.

River: (7.66 BB) 3[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
MP1 checks, <font color="#CC3333">Hero bets</font>, MP1 calls.

Final Pot: 9.66 BB