If i read this right, the 1st 3 issues are free if paying by Direct Debit, you can always cancel the DD before the 1st payment.
Price Saving Price per issue* Months Issues Details
£0.00 100% £1.62 (?) 3 3 Direct Debit
Possible £4 Quidco too (although it may not be validated by the time you cancel, but worth a try).
Quidco link: http://www.quidco.com/entertainment/books-mags/isubscribe/