The yellow bus, which bears text reading “send Boris a message, ease the squeeze”, will tour Scotland in the 21 days ahead of the elections on May 5.
The First Minister met SNP candidates on top of Dundee Law on Friday morning as she launched the bus, saying the cost of living will be “centre stage” during the campaign.
Over the bank holiday weekend, the bus will stop in nine council areas including Dundee, Perth and Kinross, Angus, Edinburgh and the three Lothians authorities.
Ms Sturgeon told the PA news agency: “If anything, this election has taken on added importance in recent days because of what we’ve seen develop around the Prime Minister.
“The Prime Minister has been found to be a serial breacher of Covid rules and has also repeatedly misled the House of Commons, and yet is refusing to accept any consequences for that.
“So this election is an opportunity for people to send a message to Boris Johnson that they find his behavior and response completely unacceptable.
“And of course it is an opportunity to put the cost of living center stage.”
Asked about how much spending power councils had to deal with cost of living issues, Ms Sturgeon acknowledged it was still a “tough time” financially for government and local authorities.
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She said the Scottish Government had offered councils an extra £120 million before the recent budget, ahead of their ask of £100 million.
Cosla has said they still face a real-terms cut in funding which could grow in coming years.
Ms Sturgeon said: “We will always work to help support local councils as far as we can within the budget that is set largely for us by the UK Government.”
Poverty campaigners have previously criticized the Scottish Government’s approach to the council tax rebate, saying it merely mirrored the UK Government’s plan to ease the burden on household finances and was not targeted at those on the lowest incomes.
Asked about this, the First Minister said the Scottish Government’s priority had been to get help to people as quickly as possible.
She said: “The way we did it was helping the maximum number of people and also allowing that help to be made available quickly.”
A more targeted approach would have led to longer waits for the support, she said.
She said the Scottish Government would continue to do what it could to help those most in need, pointing to the recent announcement of the doubling of the Scottish Child Payment benefit.
The First Minister was also asked about Scottish Greens co-leader Patrick Harvie’s comments that SNP members were being allowed to “get away with promoting transphobia”.
She said she did not agree with these comments, saying: “The SNP, like the Scottish Green Party, stands very, very firmly against transphobia.
“So I don’t agree with that.
“Albeit Patrick Harvie is a minister in my government, because we’ve got a very constructive partnership agreement between the SNP and the Greens in government, we are separate political parties.”
She said disagreements were inevitable between parties during election campaigns.