This site will tell you the bad news:

I went to Waterville yesterday - a 30-somthing mile trip. When I went through Skowhegan, the price at the Irving I usually strop at was $2.82, up from $2.57 on Monday. On the way back - 1 1/2 hours later - they were raising the price from $2.99 to $3.17! Sheesh!

This is gonna put a clamp on geocaching!