I bought in early, and kept dollar-cost-averaging along the way. I now around 35,000 NEO which are generating me about .5 GAS per hour. With NEO, and the GAS making me free money 24hrs/day, I can essentially quit my job now, as income from GAS alone could pay my bills in my Country. 
It is unlikely that you can become a millonaire buying NEO today. If you were a very early adopter and invested a ridiculous ammount on money, it is possible to live of gas, just until a better coin comes and kills your "way of life"