My mother tells a lovely anecdote about being on holiday in Sicily in the summer of 1975. She was so impressed with how the men were dressed. "Everything was so tight, from the jackets to the trousers and all the way down. Form-fitting, nothing out of place. And they were all wearing these fine, pale-coloured socks - very light and in every pastel colour you could think of.
"But I remember sitting there watching this guy smoking. He seemed undecided on where to store his cigarette pack and lighter. Anywhere in the jacket or trousers would have ruined the silhouette. So instead he tucked them inside his long, pastel-coloured socks. It was probably the one place he could put them where they'd be hidden from the outside."
So if you're worried about messing with the line of your suit, that's where to store things. Notes might work better than loose change, though. And you'd better be wearing calf-length socks.