During a bicycle tour through unknown areas, my friend and I relied on a map.
Unfortunately, neither one of us had a map holder on our bikes.
I didn’t want to buy one for these infrequent trips – they are quite expensive, and a mounting piece is permanently attached to the handlebar which bothers me.
That is why we came up with a really easy magnetic solution: I snapped a large block magnet
onto my iron handlebar.
People with alloy bicycles (such as my friend) could, of course, glue the large magnet to the handlebar.
The advantage in my case is that I can remove the magnet with the flick of a wrist.