We've all seen these apps — you spot their fancy-looking ad on your Instagram or Facebook feed, you download them "for free". Turns out, the app will only let you use it if you sign up — there's a 3-day trial, then you instantly get billed for the next month of usage. Prices usually vary between $5 or $15 per month. And, at the end, the app turns out to be nothing special after all.

Now, it's clear who these are made to pray upon — some people are not that tech-savvy, some will forget to cancel the subscription before the trial is up, some will think that deleting the app from ...