Three things not to say when you are losing in an interview:

“Just give me a chance” - Desperation is a poor motivator to a higher manager and begging…that’s what dogs do, not future employee’s.

“I would be willing to work for nothing for a month” - Most people are looking to increase production or sales by hiring you, not save money.  Position yourself as someone that can bring one or both and you will turn heads.

“I know I lack the experience you asked for but I am a quick study” - That may sound like an innocent move, but in reality it sounds desperate (too).  Better to say, “what made you determine I didn’t have the experience, yet at the same time, motivated you to call me for the interview”?  In other words, “what did you see in me on paper that you aren’t seeing in person”.