From their TOS
2.6.4 The initial 1 month provision of these services is free when a new domain is registered through iregistrations during this promotion. iregistrations normally charges a standard rate of US$39.98 per month for these services.
2.6.5 Registrant can cancel these services for any reason during the initial 30 day period without incurring any charge other than the US$5.99 already billed for domain registration.
2.6.6 Non-cancellation within this allocated period constitutes acceptance by the registrant for the continuation of and subsequent billing at the standard rate for these services.
2.6.7 Billing after the initial 30 day period is by direct debit from the registrants nominated credit card at the rate of $39.98 per month and is payable monthly in advance.