How can I afford level 30 "high end" gear?

Solution 1:

Start farming the darkzone. In one DZ run, if you extract 30 purples, you can sell them for ~75-100k credits. You also will gain DZ credits and experience, which will put you on the road to the DZ level 50 merchants that sell high-end, ilvl 31 blueprints for DZ credits. Personally, unless there is something you want to buy from the advanced weapon vendor, I would recommend you dismantle extra gear for the crafting materials.

You should also do the 3 dailies (2 hard, 1 challenging) for bonus phoenix credits. You'll definitely want a group of 4 for the challenge mode mission. If you have a regular group, you can repeatedly farm missions on challenging difficulty. This will yield extra phoenix credits, as well as the chance that the boss drops a high end item, or at least a few purples.