What kind of tires does a 2007 trailblazer SS need?

I need to know what size the tires are because I am going to buy a new set but the car itself is not with me and I forgot what size they are. Also, what brand should I go with ? I had some pirelle scorpians on them but was wanting to know if it is possible to get a cheaper tire? Any suggestions and info are much appreciated EXCEPT rude comments. Thank you