play the highest stike lvl you can for 2 reasons, strikes drop rare armor with ton of light and also strike reward you with marks that you can use to buy legendary armor.

Strikes work well to start off, then grind marks.

Basic vendor legendary gear caps out at light +33 gear and costs about 75-120ish marks. Keep in mind you can only get 100 marks in a week, so it's a solid, consistent way to get gear that's always going to be available. That being said, the way to get marks is from the strikes, and dailies. mainly the Roc playlist, guaranteed a rare engram in the final rolls most of the time. It's slow, but sometimes they'll roll into a legendary at the cryptarch. That also levels up your cryptarch rank, after every one you'll get a legendary package. Sometimes you'll get some legendary gear or an engram if you're lucky. Competing in the Iron banner while active can get you some light +36 gear if you can grind it out till you can buy it. All other +36 light gear comes in exotics from xur or nightfall runs, or crota raid gear if you get the drop. Good luck

Buy from vendor at the tower. Bam done

Just grind strikes at your best level and do vanguard bounties as often as possible to buy gear with commendations. Then the raids are your best bet for the highest rated gear