You will save money making your own soap, even though cheap nasty soap from the shop is a similar price, but from your natural soap you can make many other products that do save money. Don't forget that cheap shop soap has fillers in it like talc, besides the chemicals. Laundry detergents have also have fillers and this is what causes the build up of grime in your washing machine. Using natural soap, you'll never have to buy shampoo or conditioner again and will reduce the need for products for dry skin and allergies and acne. If you still need some of those then make your own and get a cheaper and healthier product.
If you end up making liquid soap (which isn't so hard) you will save a lot of money on shampoo, hand wash, body wash and what ever else wash they sell (even though its washing the same body - its just marketing).
Always remember that advertising is marketing. This term was given to us by Freud's nephew who used it instead of the word, propaganda.
You can make your own and make it better. To increase cost effectiveness of making your own products there are a few things you can do.
Making soap, you can tailor your recipe to the oils that are the cheapest in your area. I can get free beef fat from my local butcher (I do give them soap) and render it. It's not my favourite job but I do have the time.
You can save fat from meat that you buy and cook and freeze it till you have enough to render. Keep each different animal fat separate as they have different saponification values.
*Just note (for any New Zealanders) that Sheep Tallow soap still has a noticeable "sheep" smell. It would make a good laundry soap as it has a higher cleaning quality, especially with something like Eucalyptus oil in it.
Wait till olive oil is on 'special' as it keeps well.
Castor oil is not so cheap but its not essential. I buy mine in bulk to lower the cost. Bubbles are nice but are not everything and a little bit of milk and/or honey will increase the bubbles. If you use Lard or Tallow the conditioning will be fine. Putting a spoon of honey in the soap batter will increase the bubbles and be very good for your skin. If you have a cheap/free source of milk, make a milk soap and this will also increase the bubbles and be good for the skin.
Buying bulk is one way I can reduce my costs. Because I am not sure I would use some of my ingredients within the shelf life, I have found a few friends who are interested some of the different products and we share the cost of bulk purchases. Mostly its with Essential oils as there is a large saving in bulk purchases with these. I have just received 5 litres of Eucalyptus oil. I buy Lavender oil a litre at a time.
I don't run a business but do make soap for friends for cost price, so while I don't have a large output, it is a lot more than my family would use. If you are a person that is going to give a lot away maybe you should try selling some to neighbours or associates to recuperate some costs.
Grow your own herbs and do oil infusions. Use Basil, Rosemary, Lavender, Oregano, Lemon Grass or what ever other beneficial plant that grows well in your climate. You can dry them or use them fresh, so long as they are clean and dry from water. Use a sterile jar. Heat you oil and pour over them so no vegetation is above the oil and seal/cover. You can keep it in a warm place for 4 -6 weeks but out of the sun. Just make sure you don't use anything that may give allergies (ginger is nice to eat but some people don't tolerate it on their skin very well). You can use dried herbs.
If you grow Aloe Vera add it to your soap. Do a bit of research how to deal with it first.
While some products or home-made remedies may be more expensive to make than to buy don't forget that the same alternative treatment may require a prescription and cost you a doctors visit.
If you live in an apartment and don't have garden space, try window boxes or hanging baskets for herbs. Dry them and save them till you have enough to use.