[Simaramis]

I have thus far failed to get an answer from anyone as to what the revenue of this tax, albeit tiny, is being used for. As it stands it just pads the grocer's bottom line. Whereas it should be used to fund research and protecting the environs. But everyone is mum. At least in California.

[CalChris]

It isn't a tax. It's a minimum price. The money goes to the grocer.

  The bill also required a 10 cent minimum
  charge for recycled paper bags, reusable
  plastic bags, and compostable bags ...

http://www.ncsl.org/research/environment-and-natural-resourc...

[ZeroGravitas]

It the UK most shops donate it to charity.