To find the constant of proportionality in dollars per ticket, we start with the information that a set of 3 raffle tickets costs $5.00.
First, we calculate the cost per ticket by dividing the total cost by the number of tickets:
\[ \text{Cost per ticket} = \frac{\text{Total cost}}{\text{Number of tickets}} = \frac{5.00}{3} \]
Now, performing the division:
\[ \frac{5.00}{3} \approx 1.6667 \]
To express this in dollars to the nearest cent, we round \(1.6667\):
\[ 1.6667 \approx 1.67 \]
Thus, the constant of proportionality in dollars per ticket is:
\[ \boxed{1.67} \]