How much does it cost to get listed on Coinbase?

Could you please clarify the costs associated with having a cryptocurrency listed on Coinbase? Are there any upfront fees or ongoing charges that need to be considered? Additionally, is there a specific process or criteria that a cryptocurrency must meet in order to be eligible for listing on the platform? I'm particularly interested in understanding the financial implications of this process and whether there are any potential roadblocks or hurdles that a cryptocurrency may encounter during the listing process.