Level 3 is a tier 1 provider so in theory they should be peering for "free" with other Tier 1 providers such as Verizon.
From Wikipedia:
"However, the most common definition of a tier 1 network is a network that can reach every other network on the Internet without purchasing IP transit or paying settlements."
From Wikipedia:
"However, the most common definition of a tier 1 network is a network that can reach every other network on the Internet without purchasing IP transit or paying settlements."
http://en.wikipedia.org/wiki/Tier_1_network