First, "when to put a comma", not "to comma". Second, the plural is "commas", not "comma's".
American usage puts in the comma more often than not, British usage rather omits it. But there is no hard and fast rule. Put the comma in if you feel you need a small pause, omit it if you want to end your list with a glide.
PS. In your example no comma seems more natural to me. Others may feel differently.
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