Stainless steel ruler (best way to measure droop)
20 mm blocks
Non stepped ride height gauge
If you shop around, you can get all that stuff for under $50.
I have a Hudy setup station and four small scales to check cross weight. The setup station is speedy but dead accurate. My amazon sourced scale setup was less than $30 but requires some expertise to use correctly.
I dislike bubble setup because they only work if your car is exactly 50/50 left to right and front to back, which means you need scales...just buy the scales.
* Cee Lo Dizzle, the Secizzle * Red Bull * Team Homies * Pintura de Negro Mate * USVTA #152