...there's really no 'cheap' way to do it. Most retirees I know in an RV/etc. have opted to reduce/limit costs by finding prepaid cellular voice service that suffices for their particular price point/service/coverage needs. On top of the voice, they carry around a wifi only tablet to communicate at places where wifi is available. YMMV.
If you are an extremely light user of cellular data (e.g. light email/no heavy video/audio streaming), some sort of 'mifi' device could provide the occasional mobile cellular data if you travel in such areas away from wifi spots.
This conversation/issue gets thorny quickly since there are a whole slew of variables that need to be taken into consideration before diving in (i.e. buying new devices, signing up for new services, etc.).
At this time we each have a Samsung s4 and our service is through Verizon. We do like our service but it is what we think a tad expensive, $150.00 per month for both.
Patti retired last August and we will start doing a little traveling in our 5th Wheel.
What would be the recommendations for our "communication" usage. Is there a tablet, an ipad that will do the same for calling, texting and browsing. I am guessing the costs will probably no different from the phone. We may also try to go with a pay as you go but my guess that would put the kabosh on using an ipad or tablet. We have also been told that using a pay as you go, ex: Net10, only give you minimal usage, minimal power, coverage of cell towers.
I hope I have explained everything fully.