Depends on whether you want to remove stains or actually whiten your teeth. Pearldrops will only remove stains but won't change the natural colour of your teeth. I had my teeth whitened by a dentist who took moulds of my teeth and had plastic trays made to perfectly fit my teeth. I then received gel which contained hydrogen peroxide (9% I think) and slept overnight with the trays in for 1 month. I always get compliments on my teeth now as they lightened by several shades). Under the supervision of my dentist, it was a safe process which did not damage my teeth. If you want to change the actual colour of the enamel of your teeth you must make sure that the gels contain hydrogen peroxide - anything else is a waste of money! Personally, I think that if the trays are well made and the gels are appropriate, �99 sounds like a bargain!