My first take:
'Get your free Motomo necklace just for taking a minute to read this!'
My second take:
Get yourself free mottommo necklace just for reading this!
Is there any better way to write the above sentence something still short and sweet!
Depending on how formal you want the sentence to be,
I'd stick to the second sentence (but only if you want to come across as chummy)
Get yourself a free mottommo necklace just for reading this!
hope this helps.