I tried to explain in simple words for newcomers, hope it will be fruitful for you. Most of us mixed the concept of PPC with ACoS, yes it’s quite a complex and tricky part of the ranking. Before we launch any product we should understand the whole game.
PPC: Pay Per Click
Amazon offers 3rd parties sellers to advertise their products on the Amazon marketplace. It’s also called Sponsored ads. It’s a very important subject in ranking. Most of the clients demand to rank their product just with PPC.
PPC Types
1. Auto PPC          2. Manual PPC

Auto PPC:

In Auto PPC we just set our daily budget and select a bid against our product usually lower than Amazon’s suggested bid and let Amazon decides when to display your product ad based on the keywords identified from the title, description, and other sections from your product listing.

Manual PPC:

We have 2 major types

In Manual PCC we select some top-ranked keywords and let Amazon display our ad-based on given keywords. Usually, we select these keywords from Auto PPC reports based on the sale velocity.

What is ACoS:

ACoS = “Advertising Cost of Sales”
It belongs to the efficiency of your advertising campaign and keywords.
In simple words, the Total budget spent against your sales is called ACoS.
ACoS = Ad Spend Budget / Generated Revenue * 100
Let say, we generated $100 against an advertising campaign which costs us around $25.
ACoS = 25/ 100 * 100
ACoS = 25 %
Note: The ideal ACoS should be less than 20% or equal to your profit margin.