If you get such texts I would suggest signing up for the donotcall registry, it may or may not help. It really depends on if the people running the operation are semi-legit or not.https://www.donotcall.gov/
As far as phones go, I ended up switching off my families family plan to my own service and I have platinumtel. Which is a really minimalistic company, but for someone who doesn't use a cellphone often they have almost no tripwires to get nom your minutes and fair rates. Their tech support from what I hear is almost non-existant, but they operate off of the Sprint network, they're actually a subsidiary of Sprint.
I looked at a lot of pay as you go packages and they usually have BS in the fine print, Trachphone really tries to get you on their package deals and how they deal with minutes. They don't even have up front costs on their SMS messaging. Your minutes also expire with pay as you go plans for a lot of other carriers, in addition to having service days. If you really wanted to it's possible to have a cell phone through platinumtel for $40 for a year as long as you don't use up your minutes. They're the only carrier I've found that offers data services when you aren't on a monthly plan, which is awesome if you have a android phone and gvoice or skype. $.10 per MB.
They also give you your service codes to unlock your phone you get through the mail, so the phone is essentially unlocked to begin with. I personally rather go with a GSM carrier, but there haven't been any that have been remotely close to how good ptel is.