To calculate the sales tax, you can use the formula:
\[ \text{Sales Tax} = \text{Price} \times \text{Sales Tax Rate} \]
In this case, the price of the bench is $99 and the sales tax rate is 5%, which can be expressed as 0.05 in decimal form.
\[ \text{Sales Tax} = 99 \times 0.05 = 4.95 \]
So, Scarlett will pay $4.95 in sales tax.