I use one of these:
It does have a couple of clamps, with crocodile clips to fit on the upright, but I found them pretty useless - 2 x AA batteries in the base. Bought off ebay - no makers name. Cheap, but good enough for my needs
Dave
Hi Steven
Each to their own but I could not get on with my magnifier/light which clamped to the desk. I found it quite restrictive and awkward to use. I gave mine away. I much prefer one like John suggested or the ultimate combination of Optivisor and Triple Bright Daylight lamp.
Jim
I have a head led magnifier and a desktop mounted one. I use both quite a lot.
My desk mounted one was from MachineMart. They do quite a few so have a look to see what suits your budget. But imho their prices are very good and their service is great too.