Thumb drive or portable hard drive is widely available on local computer stores and leading online merchants, however I suggest you buy this portable storage devices at Amazon.com. One particular portable device I suggest you take a good look is Western Digital WD Elements 500 GB USB 2.0 Portable External Hard Drive, which is priced just $60.99, a discounted price from its original list price of $82.99.
In terms of Thumb drive, I suggest you consider HP v100w 8 GB USB 2.0 Flash Drive P-FD8GBHP100-EF, still available at Amazon.Com, priced at $14.88, which is on sale at 60% discount from its original price of $36.99. With regards, to your query on the most cost-effective portable storage device, in my opinion, it is more cost effective to buy a portable hard drive than a thumb drive in the sense that the former have more capacity is storing data compared to the latter.I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.