I buy the shampoo and laundry soap by the gallon and they last me a long time.
The shampoo can be diluted at least by half, I use a dr pepper bottle with a hole punched in the top because it gets watery, but by diluting it less is wasted 'down the drain'.
When asked how was business, the fella always answered 'down the drain'.
The dose for a load of laundry is one ounce, or 128 loads a gallon.
I'm not sure the laundry soap does as good a job as detergents with their solvents and bleaching agents, but it won't give you cancer from rubbing off your clothes and onto your skin.
You can buy in bulk, but don't let the liquids freeze, I lost most of a gallon of shampoo when the bottle burst.
I bought 100 bars of the bar soap in 2018 and haven't used them all, yet.
I bought the 3year supply in 2011, but I gave most of it away in the course of travelling.