Hi oli,
maybe like this:
=IF(X8="",TEXT(X8,"$0"),IF(AND($D8="united states",AN$7="Challenger"),$AG8*0.8,IF(AND($D8="united states",AN$7="SGT"),$AG8*0.95,IF(AND($D8="Canada",$I8>=20),$AJ8,IF(AND($D8="Canada",$I8<=20),$AI8,IF(AND($D8="United States",$I8>=20),$AG8,IF(AND($D8="United States",$I8<=20),$AH8,"0")))))))
but do you want the reference to be working together with existing AND's statments?