Medtronic Advice

So I've had a Medtronic 670g for about 2 years now. For someone with severe t1 as myself it has been a great improvement over pens/syringes. But after a year I couldn't afford the sensors and am now having trouble affording infusion sets, i've checked a few websites which mostly say no shipping to my state. Does anyone know of how to make Medtronic more affordable? They claim that it goes through insurance, and i've already got a monthly payment going with them, but there seems to be an ever growing separate balance with them. I've been a t1 for 10 years (currently 21) with range of 20-700 (doctors say due to extreme fluctuation in sensitivity, i manual bolus everything now), somehow 7.8 a1c as of 3 months ago. I'm afraid going back on the pens would kill me. Any wisdom on the matter would be greatly appreciated.