Hey! 10MS is really easy to get with a few days of solid gameplay. You can get Moonstone shards pretty easy doing dailies which can be crafted with Miss Mac!
You can also sell unwanted items from your inventory to the Vendor! It might not seem like much, but it adds up if you do campaign a lot or have a lot of wolves generating pebbles with Companions. Once you have 100,000 pebbles, you can usually sell it on the Flea Market for a moonstone.