Great question, tsmart95, and welcome to our Support Community!! You're actually in luck because our promo that we have for the Series 3 Watch is still going on! You can check it out here: Apple Watch Series 3 & 4: Get 3 months of service free!. In order to use the full functionality of that gorgeous watch, it'll need to be connected to a DIGITS line.
Let me know if you have any other questions!
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