You don't need any SMS's. If you use one of the apps it's live all the time you just open the app and it shows location on a map. You can also set geofences so it notifies you if it leaves the area you have set. Mind you the satellite wanders a bit so you need to be generous.
3G vs 4G distance from a repeater range is also something to consider,
as the thief will have you track to the last known location.
As for the Aldi Mobile sim pack, from post above:
How many sms's do we need a month to check on our pride and joy?
Aldi Mobile 365 day Rates
Standard SMS $0.12 each
$0.05 per MB of Data
One for the Pets:
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