Hello Sean, For weapon parts, the cheapest and most efficient way is just to stumble upon green and blue engrams. Seeing that you want glimmer as well, I don't think you want to purchase guns at the gunsmith for 500 or so Glimmer. As of Glimmer, the best way is to go to the Speaker and use your Ascendent and Radiant Materials to trade for large amounts of Glimmer. If you need more help for Glimmer, I'd search for videos for up-to-date Glimmer Farms.