The money comes from Bob Erb, a Terrace pot activist who won a $25 million Lotto Max jackpot last year and later earmarked $1 million to promote the cause of legalization.
Erb's donation is going to expenses such as office rental, printing flyers and paying two full-time staff in Sensible B.C.'s Vancouver office, but Larsen has found that mailings are taking up a heavy proportion of his budget.
"All of these actual petition forms have to be sent from canvassers to our office," he told The Huffington Post B.C.
"We're looking at easily $10,000 or more just to mail stuff over the next couple of months."
Larsen will hit Squamish, Prince George and "pretty much every town in between" next week to sign up canvassers who will collect signatures for a petition to force a referendum on the Sensible Policing Act, which would stop B.C. police from using resources to enforce marijuana laws.
The petition needs the signatures of 10 per cent of voters in every riding, and Larsen said he has 600 out of a hoped-for 6,000 canvassers signed up already.
Sensible B.C. has been endorsed by Stop the Violence B.C. (STVBC), a group pushing for the taxing and regulation of cannabis that has the support of high-profile names like former premier Ujjal Dosanjh and former B.C. attorney-general Geoff Plant.
"I'm hoping to get some positive comments and words of support out of those kinds of people over the coming weeks," Larsen said.
STVBC founder Evan Wood said the group is "philosophically in support" of Sensible B.C. but is not involved in the campaign in any formal way, though he added that he would be willing to come out publicly and support the initiative himself.
"There's obviously official support there and it's just a very difficult process of getting these different individuals and groups together sometimes," he said.
"I think people who support a health and safety approach to cannabis are certainly in support of Sensible B.C."
But marijuana decriminalization could run into plenty of issues if the initiative passes.
Kash Heed, former B.C. attorney-general and a former chief of the West Vancouver Police Department, expects that the RCMP and the provincial government will put up roadblocks to the Sensible Policing Act if it passes, The Georgia Straight reported.
"They’ll use the easy way out, and say this is a federal issue."
Heed said that marijuana enforcement is applied inconsistently in B.C., especially outside Vancouver.
"You just have to step outside of the jurisdiction of Vancouver and you find a different practice in place by the RCMP," he said.