Which exchange is best for new token with fairly low daily volume by design? So that it doesn't get delisted due to low volume
It should be free or very low cost to list
For ERC-20 tokens, Etherdelta. I don't even think there is a cost to list tokens. They add new tokens everyday, and every air-dropped token I've seen on the forums has been listed there. In fact, I'm pretty sure you can just copy/paste a token's address into the browser as "#0xxxxx-ETH" and you can start listing asks on the book before a token is officially "listed."
The volume will be lower than other exchanges, once a token gets listed elsewhere. Etherdelta is a decentralized exchange, so it's a bit slow/clunky/confusing for new users. But I prefer it so I don't have to trust exchanges to hold my ETH/tokens.