Freedom Prepaid vs Postpaid

Friend is currently with Freedom but wants a new plan that works in between subway stops but also Data works outside toronto by piggy backing off someone elses network.

I saw prepaid has a promo for 19/mo for 1.5gb that is nationwide data. (currently freedom 500 for $25 / month)

Only issue is that coming from postpaid to prepaid isn't consider a new activation so it'll be $24 a month. Is there an easy way to get the 19/mo price or just signup as new customer and port over the number?