By default, the Price and Quantity fields are set to two (2) decimal places in the Free Version of SpendMap (e.g. $123.12).

But when purchasing items with a very low unit price, you may need to increase the number of decimal places for prices, which you can do in here…
– PURCHASING > Setup system > User defined terminology and settings > User defined field settings

You might also want to consider the unit of measure that you’re using.  For example, if you purchase by the thousand (M), you’d need fewer decimal places (e.g. $123.45 vs. $1.2345).  You can set up your units of measure in here…
– PURCHASING > Master Files > Units of measure > Add/modify/delete