Unit price is the number the auctioneer settled on. What it means depends on the pricing mode:
Per cwt — dollars per 100 lbs.
Per head — dollars per animal.
Lump sum — the total price for the lot.
The unit price is always in the same unit as the lot's pricing mode — don't read a per-cwt price as a total. The gross amount is what turns the unit price into the actual dollars owed.
Technical section
Data model, API, and internals — visible to developers.