I want to do a gift give away on Facebook. How do I add a like button so they can share and like

I just set up my business page on Facebook and want to do a give away during the Holiday season. I want them to like and share my page and also make a holiday comment. I don't know how to get the like button on it. Or do I have to pay to do this? You guys ROCK! This old lady has learned so much from ya! Thanks!

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