I'm gonna get mine done Pete soon,it's going to cost me 350 the dentist takes an impression of your teeth gives you the whitening paste depending on how yellow ya teeth are he decides what strength and how long to wear it for, that's one you do at home yourself.if you have it done in the dentist i think you can pay up to 500,then once youve reached your desired colour you can get a toothpaste of them to keep it up as long as you cut down on tea coffee and red wine,you can also go back for top ups every now and then. hope this helps anyway