Based on what observations? Around here most people pay half of that as far as I'm aware - and I'm hoping that this number is even lower in low income countries.
Plus, comparing a general internet access & phone plan with a specific online service seems odd. Even if I'd trust you with this number, paying $50 for 'the internet' or paying the same amount for WhatsApp 2.0 doesn't seem direcly comparable.
We were easily paying $100/month for AT&T's "family plan." This was about 8 years ago.
We then switched to T-Mobile's pre-paid plans, which start at $40/month. That's for 3 GB of data. If you want 5 GB, it's $50/month, which comes to $600/year.
