I'd never fold here, here is one reason why.

Party Poker No-Limit Hold'em, $ Hero (6 handed) Hand History Converter Tool from FlopTurnRiver.com (Format: FlopTurnRiver)

Hero ($200)
UTG ($299.53)
MP ($410.65)
CO ($254.20)
Button ($308.43)
SB ($231.45)

Preflop: Hero is BB with A, 8. SB posts a blind of $1.
4 folds, SB (poster) completes, Hero raises to $6, SB calls $6.

Flop: ($16) J, 4, 9 (2 players)
SB checks, Hero bets $12, SB calls $12.

Turn: ($40) K (2 players)
SB checks, Hero checks.

River: ($40) 3 (2 players)
SB checks, Hero bets $30, SB calls $230.45 (All-In), Hero calls $198 (All-In).

Final Pot: $396.45

Results below:
SB has A Q (flush, queen high).
Hero has A 8 (flush, ace high).
Outcome: Hero wins $396. SB wins $2.44.