I get quotation of rm800 for a 8 ft++ high 3 ft wide formica. Is this reasonable? I personally think its a bit too expensive.

Yes, that's way too expensive. I bought mine for 80 bucks for a 8' by 4'. But then again, it depends to what type of formica yours is.

the most expensive formica i ever see cost rm400++
mayb yours have special feature? stainless steel??