I just totaled up my YTD (year to date) spending on my mobile prepaid, which is generally phone and text based. I do use secure wifi at home and at some people's places where I know it's secure safe network, and they have given me permission to do so. If I did not do that, I would purchase a prepaid plan, or look at budgeting in a broadband plan and cutting other expenses. Probably I would settle on minimal internet at home, and then use public accessible wifi.
I have been told by the IT guru that the flaw with free publicly accessible wifi is that devices that link to it are not protected unless a VPN is initiated. A VPN is a Virtual Private Network and is designed to protect your bank passwords and other details that are best kept private.
For more information about the benefits of VPN contact a provider of the service.
Anyway, my smartphone service after nearly five months totals just under $40 prepaid calls and text. I do have the odd data use in there to check with our electricity company when the power went out, or to text a photo here, and there. I guess if I added reasonable at home data use in there, while using free wifi and the purchase of a VPN I would double that easily. My usage has been conservative, the use of 4G network does seem to provide better value as long as my phone lasts for a reasonable period. A reasonably priced smart phone, over the long run, may work out cheaper than an old fashioned flip phone.