I use bubble bath for soap–but it takes more soap. I thought I was saving (and probably still am) but I have to do 1/3 to 1/4 bottle of bubble bath adn fill the rest with water because bubble bath is more diluted.
But I buy a quart of it or so at Big Lots or Dollar General for $1, so maybe it’s still cheaper than liquid soap.
I got mine from https://www.brambleberry.com (a soap supply store) for a LOT less than Pampered Chef, maybe $2 or $3 each–they’re not as “pretty” but I’ve got them all through the house and LOVE them! They are sold with the containers on that site–if anyone needs a direct link I can look it up.