For a 0-5Kg measurement, I use the $13 scale from Kmart. Its brilliant as it gives me exact weight to 1g. I have taken exact 0.500 Kg parcels to the post office and it shows up exactly the same on their scales.Touch wood, its going strong after 6 months.

Moreover, it has a raised platform which I needed for longer packages, which you probably don't need if you are weighing small packages.