If you want to send SMS, you would need to pay $10 for 6 months to be able to send SMS, (so $20 for the year), BUT you'd still need either data or wifi access in order to do that, so if you want true cellular SMS capability, might as well go with Speakout $25/year
Annual cost: $25
Monthly fee: $1.25, so $15/year; leaving $10 for actual usage.
Assuming no calls
Incoming SMS: Free
Outgoing SMS: $0.15/each
$10 for outgoing SMS: You could send 66 SMS per year.