Ipaid $6.50 and $2.90 and theres a 6 % sales tax? what did i pay?

You payed $9.96. 

$6.50 +$ 2.90=$9.40
$9.40 x 0.06= $0.56
$9.40+$0.56=$9.96

The first thing we must do for this case is to calculate the total amount paid.
 We have then:
 
 We are now looking for an additional 6% of the amount.
 For this, we make the following rule of three:
 9.40 --------> 100%
 x ------------> 106% From here, we clear the value of x.
 We have then: 
  you paid: 

The first answer is correct