So you’re paying $19 for 1GB and unlimited text/voice, plus another $15 most months for overages?
You can get 2GB with unlimited text/voice for $10/mo or $96/yr ($8/mo paid upfront) through US Mobile. You get your choice of Verizon, T-Mobile, or I believe they’re adding AT&T very soon. You can add a rollable GB for $2 a pop, but I’m not 100% sure you can if you pay up front for a year of the $8/mo price.
They also have a 10GB and unlimited plans for less than you’re paying, if I’m understanding your statements correctly.