The lock boxes are rather popular, but are considered to be a racket. I've bought hundreds and hundreds of them with no UL rings to show for it. Yet, I see the same people getting several UL rings almost every day.
But, put simply, the boxes still are a good deal as long as you aren't buying them ONLY for the rings. The universal ammo is ok if you are planning to mine or hunt. The A1 through A10 skill pills show up and are excellent for helping you to level up much faster than normal. There are pills that affect your reload rate, your health and regeneration, these are very powerful buffs that if used strategically can be of immense benefit.
Only certain pills can be sold to the trade terminal. The fireworks can be sold to the trade terminal. The pets, well, yes, the pets are dumb. You get the same kitty or panda over and over again, but I guess if you want to farm pet essence, here you go.
At this point, I personally buy the boxes for the pills. If a ring shows up, great. It is important to note, values of rings change greatly, and their values may range from 50 peds on up to tens of thousands of peds... But as more of those expensive rings are found, you may expect the prices to drop fast. Unless you plan to keep a UL ring forever, DO NOT pay the high markup. They will be a bad investment. Nothing holds a high value in entropia, because when people need to sell, they need to sell now. So, they will sell to traders, who will sell for less than markup, and pay even less in trade than they sold it for. And the process repeats, until the bottom has fallen out of the market. So, why pay 50K peds for something that in a year will be 10K? Yes, it is almost that bad I am sorry to say.
The new player may look at the auction and think, wow, there are expensive things in this game. The prices of 6 or 7 years ago were magnitudes higher on a lot of things. There used to be guns that would sell for 50K to 100K regularly. There used to be 100K ped sets of armor. There used to be a lot of high prices on everything... But a lot of people quit, and sold at any price, there is a tremendous buying opportunity I think. If you are "investing" long term... Do the research, and make sure you can wait for the right time to sell, and it may pay off on some things.
Anyways, Just remember that if you buy boxes, most of what you get will be pills and universal ammo. Or useless pets, or autoloot pills which are annoying, because a person tends to be in the habit of trying to loot the mobs themselves and not let the pill do it's job. I find them more trouble than they are worth. The exception is if you are doing a solo key on Arkadia, in which case autoloot can be your best friend. Or if a mob dies somewhere and you can't click on it to loot it, at least the autoloot pill usually works then too.
I have heard of people buying 50K boxes before they get a single ring out of them, so keep that in mind before you go on an epic search for a common ring.