I'd just give him a Rod of Prestidigitation (900 gp for a held item of it), and write out 20 random things it could do beforehand, then roll 1d20 for it. Let's see if I can come up with a good on-the-spot list:
1. Create a small implement (fork, spoon, tuning fork).
2. Move an object weighing no more than a pound.
3. Create a quiet humming sound.
4. Create an annoying beeping sound.
5. Color the wielder's hands blue.
6. Color the closest ally's hands blue.
7. The rod emits a loud, humorous quacking sound.
8. Create a small jet of flame, capable of lighting a torch.
9. Make one object taste like something delicious.
10. Make one object taste like something delicious, but smell terrible.
11. Make one object taste like something terrible.
12. Make one object taste like something terrible, but smell delicious.
13. Warm one object slightly.
14. Chill one object slightly.
15. Open 1d4 buckles and fasteners on the target object or creature's person.
16. Close 1d4 buckles and fasteners on the target object or creature's person.
17. Make target object or creature slightly slimy.
18. Make target object or creature slightly sticky.
19. The rod emits a bright flash of rainbow-colored light, but nothing else happens.
20. The rod begins to smoke violently. The smoke is non-toxic and does not obscure vision.
All effects last one hour or until another effect is used. Caster level 1. Prerequisites: Craft Rod, Prestidigitation. Because of the highly reduced effects (and the lack of choice) I'd suggest reducing the price to something along the lines of 200-300 gp. Or, you could make it also act as a Command-word activated item of prestidigitation (so you could use it for whatever you want, as per the Prestidigitation spell, at will- or you could just use a random effect instead) for 900 gp.
How does that look?