Buy a used all season camper and live in that while you build the house yourself. When you are done building sell the camper
My advice as well.
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But that does not answer the question. A buddy of mine inherited a trailer park when a family member passed. He learned very quickly about that business and mobile homes in general.
A new MH is a bad investment.
Mobile homes in good enough repair to rent out or live in will cost a minimum of X dollars. Back when & where I spoke with him, that was $15k. He had bought several used MHs and they all worked out that way. He'd pay close to $X and with a little more cash could get it up to code and serviceable. Others, he'd pay a fraction of $X but have to sink serious cash into it to get it rent-able.
He hated double-wides, as the cost/sqft he could rent them for was less than a single.
Get ready to be cold in the winter and hot in the summer.
Regards,
deadlift_dude “The very first essential for success is a perpetually constant and regular employment of violence.” ----Fred Rogers