The Mecca for HiFi in Singapore is :
1 Coleman Street #04-36 The Adelphi Singapore 179803
This is however for Hi End Hi Fi.
Maybe Sim Lim Towers of the shops in Sim Lim Square, ground floor will offer lower end products. Watch out, the Salespeople at Sim-Lim are notorious, often quote High prices and seem to bad mouth Indians. I have stopped going there.
Bargains in Singapore ? I dont that is possible. Their Currency and prices are so high, I doubt if ANYTHING in Singapore is a bargain.
Better to go to Malaysia instead...