$195
Total with tax
$1249.99x0.04 = $1299.98
Total for monthly payment for 12 months
$124.58 x 12 = $1494.96
Subtract both totals
$1494.96 - $1299.98 = $194.98
Another way…
Total with tax $1299.98 \ 12 = $108.33
Subtract given monthly payment
$124.58 - $108.33 = $16.25
Multiply $16.25 x 12 = $195