A new agreement between the TTC and GO Transit will save riders money on their fares when hopping from one service to the other.

According to Mayor John Tory's office, anyone transferring from the TTC to the GO system or onto the Union-Pearson Express will receive $1.50 off the fare price. Alternatively, if you've paid a GO or UP Express fare, you'll get $1.50 off a TTC fare. Both discounts are contingent on passengers having a Presto card.

"Ultimately, this agreement will mean if you ride a mix of the TTC, UP Express and GO to get around Toronto, transit will now be less expensive," said Don Peat, spokesperson for Tory, adding that this is a critical step toward fare integration — a key plank of the mayor's SmartTrack plan.

"This is the first step in fare integration, not the only step and not the end of the story, but a great beginning," Peat told CBC Toronto in an email.

Tory campaigned on the promise that the cost of using the SmartTrack network will be equal to a TTC fare.

The province has committed to reimburse the TTC for the money lost on the reduced fares, meaning the TTC's budget will not be affected by the new deal.

Metrolinx, which operates GO Transit, currently has 12 co-fare agreements with local transit services around the Greater Toronto Area. At a recent board meeting, GO Transit heard a recommendation to implement co-fare deals throughout its entire system.

"Co-fares are a wonderful incentive to get people to take transit," said Anne Marie Aikins, spokesperson for Metrolinx.

"They work fabulously, getting people to take local transit to our GO stations, get on the GO train and come into the city."

The agreement is expected to be formally announced at a news conference on Friday.

Steven Del Duca, minister of transportation for Ontario, called the agreement "fantastic news" for public transit users.

"These commuters will now not only enjoy enhanced service across the GO network, but also a substantial savings for choosing to take transit to get around the GTHA. I look forward to providing further details in the coming days," he said in an email statement.