Please recommend a cheap clothes washing liquid

[ifonly4]

We're having to make a large reduction in our spending, so looking at all ways to help, and need some more clothes washing liquid. Can anyone recommend a cheap clothes washing liquid (prefer liquid, but could use powder guaranteed to dissolve).

I buy the Costco own brand washing powder.

I get a huge tub for about £15 - and it lasts me over 6 months.

don't need to use much, so generally dissolves very well anyway.

Aldi everything!