What is the 2.9% 30 per successful card charge?

Could you please clarify what you mean by "the 2.9% 30 per successful card charge"? Are you referring to a fee structure associated with processing credit or debit card transactions? If so, it seems like you're mentioning a fee of 2.9% plus an additional flat fee of $0.30 for each successful transaction. However, without more context, it's difficult to provide a definitive answer. Is there a specific scenario or service you're inquiring about?