MWP only makes about 1.5M per year. Next year is a player option for MWP, so he could elect to opt out or TOR could just buy him out this year. The key is Felton. Lowry is off the books next year, so taking Felton on means taking 2 years, 6M total extra. So if you are considering them getting Lowry + Metta, they are taking anywhere from 6-8M extra.
Typically, a late first rounder costs 3M to buy outright. TOR, in principle, would be paying 6-8M for that pick since neither player can be considered an asset to them.