In article ,
"Christian McArdle" writes:

You can buy bags of ready mixed bricklaying mortar (i.e. just add water).
Still 25kg bags, but at least you don't have to measure it out, and they're
pretty cheap. If you're lucky you might find a 10kg (or even 5kg) bag, but
I'd be surprised.

My little local hardware store sells small bags.
However, it's damp sand and a separate sealed sachet
of cement inside, so you still have to mix it yourself.

--
Andrew Gabriel