Ya, my recommendation
General Hydroponics pH drops. Available at just about any hydroponics supply vendor, and runs about $7 depending on where you get it $8 tops. One bottle lasts me well over 6 months. I can make it last even longer by only filling the test vial about 1/4 the way with
nutrient solution (instead of half way), and then all I need to use is about 2 drops of testing fluid. It never needs calibration, or batteries, and there is no chance of false readings that are common with electronic meters.