The DIY Clock has a subtly pleasing symmetry, doncha think? Just you, some black foam Roman numerals and a bit of creativity. Oh and some Blu-Tack maybe. £29.99 ($48.28).
You chose where and how far apart to stick the twelve roman numeral numbers (they all have simple peel off backs), and then hang the mechanism with its distinctive classic metal hands in the middle. The numbers will stick to pretty well anything – but if you want to keep changing the design of your clock (say from round to square) then use something like bluetack and you can move them around whenever the whim takes you.