I haven’t researched it too hard, but last I checked, the main ingredient in the laser whitening treatment is a peroxide gel. The laser is used as ‘activator’. I’m open minded, but I wonder if the laser is just a cover for a peroxide treatment.
You can buy H202 for 50TWD at a hardware store.
Obviously it’s dangerous if you get the mixture wrong, H202 can wear off the enamel… I would go for activated charcoal before peroxide, as it’s much safer.
I could be wrong, but it seems like they are massively jacking up prices for a treatment that costs them pennies.