Generally, you can expect:
* Lower MPG: Older models (especially those with larger V6 engines and 4WD) will likely get in the range of 15-20 MPG combined (city and highway).
* Higher MPG (relatively): Later model years (closer to when production ended) with smaller 4-cylinder engines and 2WD might achieve up to 20-25 MPG combined. However, even these figures are on the optimistic side, depending on driving conditions.
To find a more precise estimate, you should specify the year, engine size (e.g., 2.2L 4-cylinder, 4.3L V6), and drivetrain (2WD or 4WD) of the specific S10 Blazer you're interested in. Then you can search online (e.g., using Google, Edmunds, or Kelley Blue Book) for its EPA estimated fuel economy.