New player here. If I am buying cards from Amazon, how can I tell if I am buying LCG cards versus CCG cards?

If it doesn't say in the description I would say get the name of the product you are looking to buy and cross-reference it with a site like Dabbler to see what era it is from (Dabbler's site identifies whether a block is CCG or LCG).

Or simply check the Products section for A Game of Thrones here on the site. All items listed are LCG.