A free app for Android, by Sylnet VPN Groups.

A virtual private network (VPN) extends a private server across a public one, allowing users to send and receive data as if their operating systems were directly connected to the private network. It establishes an encrypted tunnel to safeguard your confidential data and communications, conceals your IP address, and allows you to use public Wi-Fi networks safely. It can protect your online identity, protect you from attacks associated with unsecured public Wi-Fi channels, and assist you in circumventing various arbitrary constraints.

One of the best VPN service app for Android is Lion VPN. Best of all, you can download it for free.