what's the difference between manufactured disc and disc that we burn at home?

Hi friend. Those cds you bought from store definitely have higher quality probably because they use special software that is not available in the market only for recording companies like them. Another factor is they use higher quality of the cds itself that's why it's much expensive compared to just burning your own cds.

A bought CD or DVD is pressed in much the same way that the old vinyl gramophone records were pressed. The difference is that the disk is in two parts sealed together. The face carrying the data is actually inside the disk, so a few light scratches on the outer part will not have too much effect. The burnable ones are a "liquid" chemical similar to LCD's. They are much more sensitive to scratches, heat, and magnetic fields. The pressed disks are generally cheaper to produce in high volumes.

Commercial CDs/DVDs are pressed and not burnt. The first one were said to last more than a thousand year ; actually you read more often a century... if you don't scratch or broke them before. Anyway, I doubt that we will be able to read them in a century -- I have still a working 3 1/2" floppy reader, but finding a 8" reader is more difficult today --.