I am using coopers tablets for priming - not particualary good as I am using 500ml bottles so I should need 1 1/2 tablets

So my question is, what can I use as primer for 500ml bottles generally for bitter and lager kits? Can I just use granulated sugar? If so, how much?
If I want to experiment, can I use other sugar products? Again, how much for a 500 ml bottle?
Cheers
Jim