Depends on what you want to test:
Guillotine - at the level you're at, you'd only really be able to use it to get a feel for degree of fermentation. It will be useless to determine insect damage or mold at this stage. It's more of a qualitative test for fermentation, and not a terribly accurate one at that.
Moisture meter - get a dickey john portable, or an aquaboy with a small sample adapter. Good for rapid, nondestructive testing for moistures < 20% (good to quickly determine if drying is sufficient or not). Be prepared to spend a few hundred bucks.
pH meter. Lots of small hand held devices available. Question would be why do you want it? What is it you're measuring - pulp pH? Whole bean? And what would you do with the results - how would you use them? <$200. Get calibration fluids for 1, 5, 7 pH. You won't need alkaline.
Refractometer - similar to the handheld pH meter. What would you do with it, how would you use the results? < $200.
I'd start with identifying what parameters you want to control / track, then determine what equipment you need to do so.