Being down to the last few scoops of commercial powder was just the push I needed.
I bought all the supplies from my local Foodland supermarket.

There are hundreds of recipes out there.
I settled on the one on the Borax container!
1 bar velvet soap 4pk 500g $3.03 - 1 bar 0.75c
1 cup washing soda 1kg $3.15 - 1 cup 0.78c
1 cup borax 500g $3.99 - 1 cup $1.99
Total $3.52 for 600g
1 tbs per load = 0.11c
I grated the soap on a fine greater.
Really easy, I thought this was going to be areal chore.

Mixed it all together and gecided to run it all through the food processor to get a finer crumb.

looks like real washing powder!

I been using it for 3 weeks now and am really happy.
Smells great, I really love the lemon smell of the velvet soap.
Id also like to make my own dishwasher powder and liquid hand soap.