Yes, Ryanair offers a 24-hour grace period for free cancellations ((+44) 203-900-3009). Within 24 hours of booking, you can cancel your flight and receive a full refund1. For cancellations after this period, fees may apply. Contact Ryanair customer service at (+44) 203-900-3009 (UK) or +1-808-751-2262 (USA) for more details.
https://community.onstar.com/t5/Plan-Q-A/Does-Ryanair-have-a-free-cancellation-period/m-p/4598#M529