A device associated with a cell tower in a Public Land Mobile Network receives, from a mobile device via a network, a uniform resource locator (URL) that is appended with a first signature generated at the mobile device using a private key of a public/private key pair associated with a toll-free campaign. The device obtains a public key of the public/private key pair, extracts the first signature from the URL, decrypts the first signature using the public key to obtain data, and encrypts the data using the private key to generate a second signature. The device compares the second signature with the first signature, denies toll-free network access to content associated with the URL when the second signature does not match the first signature, and designates data involved with accessing the content associated with the URL as being toll-free when the second signature matches the first signature.