We don't let our tanks go completely empty. One of our vehicles can be $75. Ridiculous! Thankfully we only drive it three times/week, but the trip is 75 miles round trip.

Here regular is about $3.41, but we only use super unleaded. (DH used to make gas at a refinery and knows that it's the only gas that is best for our cars...90 octane or better, he says).