At least with Walmart, if you don't like it after trying it you can get a refund, so the only thing you lose is just time and some gas for travel back for the refund.
It does look like you are planning for the longer term after your initial 3 month jaunts. A crappy bike, or heavy bike gets tiring and boring awfully quick. As others have suggested, deciding on better/more compact fold, or an lighter weight bike with better components goes a long way in terms of ride enjoyment and travelling comfort.
I have an old walmart NEXT folding bike that is still in the corner of my workshop - cheap and heavy - and I can't even give it away to my kids. My MuSL is my perfect commute and travel companion, although I still get Brompton envy gettting in a tight train cab.