A lockbox doesn’t do a whole lot to deter thieves if they can just grab the entire thing off your shelf, but this compact Master Lock 5900D includes a built-in security cable so you can secure it to something solid. So you could, say, attach it to some pipes and use it as a tiny at-home safe. or secure it to a heavy cooler at the beach if you want to make your phone harder to steal when you go for a swim.
This thing’s been around since 2012, but today’s price is the best Amazon’s ever listed.