That will typically be a decentralized platform where you can do your transaction peer to peer, but as they say that you cannot have your cake and eat it all, if you want a very fast transaction that will be executed within a short period of time, then centralized exchanges would be the best because they have the volume, but you have to pay for the price which is the fee that you are trying to avoid from what I can see which I personally don't think their fee is that much for the services you will get from them.

If you chose to use a decentralized exchange where you will get zero fee or very minimal fee, you should be ready to wait for like everlasting to get a transaction done, so the choice is your which I will advise that you look more at centralized exchanges for faster turn over.