Shut off and will not start?

It was working fine yesterday then on my way home from shopping my radio shut off and so did the gas, odometer and speedometer info. Then a couple seconds later came back on then after a minute or two off again. I turned off the radio and A/C and made it home. Seemed to be driving okay and did not stall. I was looking at Carvana and put info in to trade in the car and it started but stalled after 2 minutes. What would cause this to suddenly shut off? I was just at the mechanic last week and he did mention spark plugs and an oil change (I keep up with that) among other things but did not want to spend $1,000.00 to fix just to trade in 2 weeks later.