This government page is fairly clear. As a returning resident or a visitor intending to stay more than 72 hours you may bring total goods amounting to MYR 400 without paying duty (plus some items like new clothing). If you bring more than that (currently a bit over US $100 value), you pay 30% on the excess, so if you brought MYR 450 worth you would pay 15 ringitts.

It's not clear whether the "value" includes US sales tax, but typically the exchange rate used would be that in effect when you arrive, not when you purchased the items.

This government page is fairly clear. As a returning resident or a visitor intending to stay more than 72 hours you may bring total goods amounting to MYR 400 without paying duty (plus some items like new clothing). If you bring more than that (currently a bit over US $100 value), you pay 30% on the excess, so if you brought MYR 450 worth you would pay 15 ringgits.

It's not clear whether the "value" includes US sales tax, but typically the exchange rate used would be that in effect when you arrive, not when you purchased the items.