So if buy book from overseas, can claim the amount paid, or just on the book price only cos sometimes the shipping cost more than the book....

I've read Seksyen 127 (you can find it in Income tax Act and read it yourself); In sum: doesn't affect most makan gaji/office/corporate workers. Ignore and proceed.

You can Google the Tax Act; it's in there. Doesn't apply to most makan gaji people. It's too long for snappy summary.