Compared with many other cities in Mexico, Ensenada is a bit on the expensive side. However, most expats see it as inexpensive compared to where they come from, especially the many Californians who have made Ensenada their home.
Your cost-of-living will depend upon the type of lifestyle you want to have and may be similar to what you left in your home country, if you want to maintain that same kind of lifestyle.
For a beach community, prices are quite reasonable, especially when compared to more expensive international resort cities like Cabo San Lucas in Baja California Sur.
To compare the cost of living between Ensenada and where you live, visit Expatistan or Numbeo, two popular crowd-sourced cost of living websites.