You have a cruiser, usually if you can store and transport one full size, you can do so with two. What's the problem you're hoping to solve with the folding solution in full size? When it's full sized, especially when looking for a more tighter budget solution, you might benefit more from another solution.
A good LBS, local bike shop will get it adjusted and include a year of free tune ups and better support, can make it worth the extra $50-200. However, I get if they can't get, don't have the folder of interest or only offer ones way out of your range, then I get how that can not pan out. Especially new to cycling, an LBS of good reputation can really grow your knowledge, community and provide a certain security.
Also, if you join a local coalition, or other cycling non profit organization, especially one with free classes, you might connect to a person that has or knows of someone with a folder, get up to 10% discount at your LBS, etc.
Unless its the ebay local pick up, so you can see it in person, where a return is an option, then I don't see the benefit. Sounds like a good way to end up dissatisfied. At least with craigslist, you can inspect and test before buying, even though it though there's monitoring, while waiting and a lot of junk. I kind of wondered about the Columba's on Amazon, but while better supported that still has its online shipping support and return headaches. Probably cheap for a reason. Even the evils of "big box" stores (Walmart, Sports Authority, REI, etc.) will have friendly return\warranty's, although not sure about them having a full sized MTB folder or not.