Soil Sampling Equipment Recommendation:

Option One:

JMC Environmentalist's Sub-Soil Probe ($2250-5350)
By far the best option. This probe features a sliding drop-hammer and a foot-operated jack. Great system for all soils now and more capabilities later.

Option Two:

JMC T-Handle, Mallet, and JMC Sampling Tube ($170-$805)
Inexpensive method for sampling hard soils.