Generally, what you pay for is what you get. i.e. the cheaper it is, generally the lower the quality.
Before you buy any liming material, check these details.

	Neutralising value (NV) NV tells you the lime's capacity to neutralise soil acidity. Pure calcium carbonate has NV of 100, which is the standard. Ideally, NV should be over 95.
	Fineness (Effective NV) The finer the particles of lime, the faster they react with soil. Lime manufacturers have to specify the percentages of different-sized particles in their product.

Then check out the value for money
You can compare the value of different liming materials by checking NV and Effective NV against the soil-applied cost.
(The following model does not apply to Gypsum because it is not intended to reduce soil acidity - the degree of solubility of a gypsum is a primary measure of effective quality; the higher the solubility, the higher the effective quality )

Calculation:

(Effective NV x NV)  ÷ 100 = Efficiency                           (Spread cost x 100) ÷ Efficiency = Effective cost

For example:

Lime B, even though $15/tonne more to buy and apply, is comparatively much ‘cheaper’ because its far more efficient at neutralising acidity than Lime A.

Lime A & B are actual lime products available from quarries in South Australia. Even though Lime A is $15/tonne less to buy & apply, Lime B is what we recommend. This is because the efficiency of Lime B is nearly 3.5 times better than Lime A. We only offer products that offer the best 'Effective Cost'....i.e. best value for money.