content: They're LG G5's.  Relatively cheap phones you could buy from craigslist or ebay.  Could have even bought them broken in a lot and repaired them as they're clearly technologically adept  The guy is relatively well off financially.    Also spending six months on a side project isn't really that long.  It's not like it's six months of only one thing.  Just off and on fine tuning and brainstorming until it's ready.  Yeah theres an ad, but that's capitalism.