A superb app

That is actually the best tracking app I’ve been used so far.

The app is indeed free, although for a full-performance you must pay $1.99 a year.
Limitations include:
1) you can track max 3 parcels
2) no notifications in Notification Center or bouncy icon in the dock

The second one is actually rather disappointing but still, great app.

MadameRazor about Parcel - Delivery Tracking, v2.0