How would you answer a question describing your experience in quota or commission based sales?

It depends on what the question was. If the question was, "Describe your experience in quota or commission-based sales," I would answer by sharing with the interviewer which jobs I had that in the past where I had a sales quota and/or earned commissions.

I would then go into a bit more depth on each of these roles, and describe the job itself and talk about how I performed in the role. When interviewing for sales jobs, the interviewer is likely looking for 1) whether or not you've had experience in doing so (so you should identify the jobs where you did), and 2) how you performed in that role (share your performance to plan, sales numbers, achievement).

Sales is a very performance and results-driven environment, and one of the best indicators of future performance is past behavior.