every printer coy also like that isn't it? but there will be price difference also rite? Just that laser toner cartridge are unlike the ink based ones, u can't find it anywhere on normal IT shops or S.C.
You can try those office supply companies that deliver to your office. Usually 10-20 bucks off.
The other way is for you to buy the toner powder from Singink (Level 5 of Sim Lim Square) and refill yourself. For HP I think you need a kit to burn a hole in the cartridge yourself, pour in the toner powder, and put on a rubber cap. For Brother and Samsung you just open the existing cap and refill yourself.