I did my SNSI open water diving certification for $250 with Chalo Tours on San Cristobal. Glad I did it here and in The Galapagos. SNSI is much cheaper than the PADI certifications in The Galapagos which cost around $500. You can also pay an extra $100 if you also want to dive in Kicker Rock. If you snorkel, dive or get your certification with Chalo Tours, tell them Vincent sent you, for a fair price.