Villian is your typical $50 NL donkey.

Party Poker No-Limit Hold'em, $ Hero (9 handed) from (Format: FlopTurnRiver)

saw flop|saw showdown

CO ($36.35)
Button ($9.10)
SB ($54.92)
Hero ($50)
UTG ($43.75)
UTG+1 ($97.68)
MP1 ($73.80)
MP2 ($53.25)
MP3 ($11.80)

Preflop: Hero is BB with A, 5. SB posts a blind of $0.25.
UTG calls $0.50, 7 folds, Hero checks.

Flop: ($1.25) 8, 2, A (2 players)
Hero bets $1, UTG calls $1.

Turn: ($3.25) A (2 players)
Hero bets $2, UTG calls $2.

River: ($7.25) J (2 players)
Hero checks, UTG bets $15, Hero ???

Is he bluffing, or does he really have a better ace? FWIW, I was planning on check-calling a reasonable bet.

Fold it. You have no kicker.

In fact, I check the turn since it's wa/wb with your chance of being called by an inferior hand smaller than you being beaten.

Overbets here usually aren't bluffs. Remember that EP limps are often big aces, SC's or medium-small pairs.

Thanks for the sanity check boys. I folded, but second-guessed myself for a bit afterwards. I'm glad I did the right thing.