Hmmmmm... The cheapest banquet is $88. Link: Banquet Menus

a la carte could be cheaper depending what you order. It could also be more expensive.

But most people would like a drink, which then adds to the bill as drinks aren't free... You might theoretically be able to do it for $50, but I would allow double that as a rough guess.

You could do Din Tai Fung in Wisma for $20-$25 a head (+ drinks).