There is no way. You have to grind. This game IS grind, and every decision Bungie has made since the launch reinforces that even they know that there is nothing else to it. And you're right, you shouldn't buy anything that you think isn't worth the price. The fastest way probably is to do strikes on the hardest possible level you can. Which is probably useless, since without the DLC you can't get lvl26 strikes, and they took out the awards from lvl24 strikes. So, uh, yeah. If you have friends on higher levels, ask them to take you on nightfalls and weeklies for gear and coins. When I thought for a good answer to your question, I realized how much they're pissing on the non-DLC players. Their already limited content was stripped even more. I feel dirty for supporting this game and company, I had no idea they (Bungie) would go down so fast and reduce themselves to something like this. I still play it, but it's more like a habit that's hard to drop instead of actually having fun.