Signal is the world’s most widely used truly private messaging app, and our cryptographic technologies provide extra layers of privacy beyond the Signal app itself. Since launching in 2013, the Signal Protocol—our end-to-end encryption technology—has become the de facto standard for private commu...
See I would go with the $5 one with the thought process that almost no establishment let's you charge under $5, so if I ever saw something for less than that it would immediately be a redflag.