You might want to go back and read the Terms / Conditions; this one stands out to me: Requires eligible wireless service. If you cancel service, your installment agreement balance is due.
Details: NSTALLMENT AGMT: Credit approval may be required. For eligible tablets, connected wearables, cameras, basic and quick messaging phones, AT&T Wireless Internet and other connected devices. Excludes smartphones. Tax on sales price due at sale. Requires 20-month 0% APR monthly installment agreement and eligible service. Divides device retail cost/price into monthly installments. $0 down available for well qual. credit. Limit as low as 1 device at $0 down. Down payment: May be required and depends on a variety of factors. Down payment if required will be either 30% of sales price or a dollar amount ranging from currently $0 to $400 (amount subject to change, and may be higher). Service: Eligible postpaid voice and/or data service based on device type is required and extra. If service cancelled, remaining installment agmt balance due. Activation Fee: $30/line. Restocking: if returned w/in 14 days, fee up to $45 applies. [Examples: Retail price of $779.99 monthly price for 20 months with $0 down is $39 per month, with $234 down (30%) is $27.30 per month, or with $400 down is $19 per month.] Limits: Eligibility, device, line and financing limits (as low as 1) & other restr's apply. See your Retail Installment Agreement for full details.
Dave