Use up what you have
Many people have bits and pieces of different toiletries in their bathroom cupboard. Have a sort through and use up all of the old things before you buy any more. You may find that they last you a really long time. They may be things that you would not normally use, but try them out and see whether you think they would be worth trying for a while.
It is worth taking a look at own brand products in the supermarket or chemist. These could be very similar to the branded items and cost a lot less. You may even find that they work better for you. Have a good look at the different ones available and consider whether you think you would like to try some cheaper alternatives. You may find that they are not such good quality but consider whether you think they would be good value for money.
Cheaper shops / online
You may be able to find the products that you always use at lower prices. Consider searching online or looking in different shops to see whether this is the case. You may be able to bulk buy, get cashback or generally find lower prices. It could end up saving you a lot just as a result of a small bit of research.
Sales and vouchers
If you are loyal to particular brands then get on their mailing lists. They will then send you details of any reduced price offers and they may send you vouchers from time to time as well. Also look around online too, especially if you are about to make a big purchase as you could make a significant saving.
Make your own
Some people make their own toiletries and find that it works out a lot cheaper. You may need to buy ingredients in bulk but they could last a lot longer than what you buy form a shop. It is worth investigating recipes and priced. You may even be able to sell what you have left over to your friends and family and get some of the money back.