Pre-fab/tiny homes, are they real?

Okay so for starters, my parents have land and a well and septic, etc. they bought a couple acres and hoped to one day turn it into a family compound and now I’m trying to figure out how to accomplish that on a tight budget (I am a single mom) so I’ve been exploring some options. One thing that pops up are the prefab homes on Amazon and other websites and I’m trying to figure out if those are legit or not. We do live in rural Ohio so I’m just trying to find the cheapest way to build a house, it’ll be considered a “guest home” on the property. Any tips would be greatly appreciated! I also considered buying a shed and converting it myself but I’m not the most skilled person and would have to hire someone to do most of the work. I could lay flooring and paint and everything but as far as leveling the ground, drywall, plumbing, electricity, etc I am totally lost. I’d like to stay under $50k and am willing to do some work, the quickest route possible or the pay as you go route works too. Just wanna do something sooner rather than later because I suck at saving money. It does have to be a two bedroom and it does need laundry and bathroom hookups!