Anything that is not too small that measures to the nearest gram (or 0.1 grams) will suffice. Top has to be able to support a racquet and you should be able to see the panel. Should also be tare-able and 'calibate-able' if you want bells.
I use one of the small $10 food scales from Amzon. I cannot place my racket directly on the scale. So, I put a plastic cup on the scale then turn it on. The scales sets itself to zero grams. I then put my racket on top of the cup. Works fine.