WPS in a few months may have 250ml of working solutions mixed up - and I presume the same to the stop bath and fixer But i will see how much it cost. I guess like other things here with film, they will charge a pretty penny for it and it would probably be less economical than their OEM packets off the manufacturer which is already 2x or 3x to the USA.
I think it would be $$ and if it is might just get some chemicals from the USA like Ilford which is allowed to be shipped when I buy my film. A powder might be the best for me being 1/4 or 1/5 of liquid developers. For me even with the powder - it would probably expire than me not using it up, hahah. I could buy it when I need to collect my film up ... 3x or 5x with that fration ratio ... so it's the same or more than the the longetivity of liquid developers.