I haven't had one for like 4 years, but I believe you only need to pay for one if you want to post apps to the app store. You can just do locally development for your own devices and stuff for free. You will just need to register each device within your dev account (can have like 100 per account) and then you can put the dev apps on there. If you are just doing it for yourself and family you could just register the devices and then deploy em to those.
When I was doing more of it I had like 4 of my own devices and my wife's that I would deploy to and test since they were drastically different devices resolution/performance wise, and I was also doing some online stuff where I'd have to test out video chat.
So unless things have changed, you should be able to do what you want for free without paying for anything.