Here is a listing of compact SUVs with 3rd row seatings. The Toyota Rav4 is an efficient car that offers good fuel mileage along with 3rd row seating. The Mitsubishi Outlander is the next best model that is the same regarding fuel mileage. The car also has third row seating. The Hyundai Santa Fe is a really great model that is also available with third row seating. Hyundai Santa Fe, Saturn Outlook, GMC Acadia, and the Honda Pilot also offer the same option. Almost all of them are ranged in the $22,000- $30,000, but you will be able to get optional third row seating in many more compact SUV models.
For more info, see Comparing the Best Selling Mini SUV Models: A Buyers Guide