Prodigy1Most businesses define inventory costing on a FIFO or...

Prodigy1

Most businesses define inventory costing on a FIFO or LIFO basis.

FIFO=first in First Out,
LIFO = Last in First out.

Your choice.

If you change from LIFO to FIFO your reported profit changes and the Tax man comes knocking.

For a small trader less important, but if you want to analyse profits, so long as you stay consistent it shouldn't matter too much.