What is the difference between base price and unit price?

Base price is the cost of a basic version. Most people will want a few extras which will increase the cost. Look at the sticker on a new car. It starts with a base price and just keeps growing as options are added. Unit price is the cost for one item when multiples are usually purchased together. Look at the stickers on the supermarket shelf. The usual "unit" used on these is an ounce. An 8 ounce bottle of juice that sells for 88 cents will show a "unit price" of 11 cents per ounce.