Arbitrage between McDonalds burgers doesn’t really work. It’s not a meaningful open market - someone paying $1/burger can’t go in and buy 100 burgers and sell them to someone else for $3. For one reason, it’s illegal. For another, no one would buy them, they’d think it’s a scam.
At least in most areas of the US, selling food is illegal without various inspections, a clean commercial kitchen, and so on. There are usually exceptions for homemade baked goods and prepackaged goods, but nothing that would apply here.
