My 32-Gbyte Toshiba thumb drives cost about $20 apiece at MicroCenter. I use 4 of them for backups: (last month, this month) X (odd days, even days). They have all my business & personal files since 1986. They have proven reliable so far. (The Verbatim ones I used for a while did go bad.) At the end of the month I copy the last day's backup onto a DVD-R.