Cost drivers include whether you are converting existing basement space or building new, whether a separate entrance and egress windows already exist, and whether the electrical panel can handle a second unit without an upgrade, and each of those can move the total significantly on its own.
A permitted suite also needs to pass the same inspection standards regardless of budget, fire separation, ceiling height, smoke alarms and proper ventilation, and skipping any of those to save money produces a suite that cannot legally be rented or counted toward a mortgage. A separate home inspection on the finished space, typically $400 to $600, is worth doing once construction is complete.
Get a specific quote from a licensed contractor for your own layout rather than relying on a generic figure, since Joel can then tell you what a permitted suite is actually worth once it is built. Get your hand-reviewed valuation from Joel Dyck.