I did an experiment and found that, cloaked, I could collect, on average, about 600 boxes per hour. From those 600 boxes I got 78,500 credits, 2,400 uri, 30 galaxy gate generators, and 3,000 rounds of laser ammo. The 30 gg generators gave me another 3,000 rounds of laser ammo, 56 rockets, 1 repair, 46 xenomit, 2 mines and a gate part.
If you boxed for 10 hours (over several days probably), you would have 785,000 credits, 24,000 URI, 60,000 rounds of laser ammo, 560 rockets, and a few other things. You could then use the ammo to hunt npc's and earn some additional credits and URI. If you keep doing this, and are successful at bidding, you will eventually end up being FE. It will take a while time, but YOU CAN DO IT FOR FREE!
There is an "art" to boxing effectively - here are some hints:
HINT: Box diagonally on a map - you can see more of the map if you are moving your ship diagonally. If you don't like going that way, at least box up and down, again you see more of the map that way than if you box going left and right (which is the way most people box).
HINT: You find more boxes on the very top and very bottom of a map - many are in the radiation zone. I think this is because people don't bother to look there. Make one pass as close to the radiation zone as possible to see them.
HINT: Very few boxes are found on left and right edges -I don't know why -I just never found many located there.
HINT: If you want to seriously box - get a cloak. Without one you are constantly being bothered by NPC's. You are also distracted when you box from looking at the mini map for enemy ships -- and are easy prey for an enemy ship if uncloaked.
HINT: Different maps seem to have more boxes in certain areas. 3-2, for example, has a lot of boxes toward bottom left quarter of map. 3-8 has a lot of boxes just to the left of the base.
HINT: If you find a "trail" of boxes -- keep going in the direction they lead you -- they often lead to more boxes.
HINT: The more npc's that get popped, the more boxes there are. If you pop an npc, usually within 10 - 15 seconds a box appears close to where the npc popped. It may appear just outside your window of view so look around.
HINT: You can always "box/hunt" -- box and pop npc's at the same time. Or if you are popping npc's and see a box - pick it up. It might be something good!
HINT: Don't box going at a fast speed. WIth the lag you can go so fast the boxes may not appear in time for you to see! Go for a few seconds, then slow down, then speed up, etc. You will see see more boxes if you move your ship a bit slower than "full speed."