My daughter will shortly be travelling around Europe with an iPad, staying in all sorts of dodgy hostels etc. I want her to use a VPN so she can have more protection when using wifi connections.

I've been playing around over the last day or so with Avast secureline on my iPad so I've discovered how easy it is to switch the VPN on and off using the switch in Settings. I've also discovered it won't connect via my work wifi.

The VPN will need to be cheap, easy to use and have a very good chance of working on different wifi's.

It won't be for breaking geoblocks or for torrenting.

What are your recommendations for VPN services given the conditions above?