To get this achievement you must play from 1-1 through 4-4 without picking up any gold or jewels. The achievement unlocks during the short cutscene after 4-4. If you do obtain any treasure, the achievement is void; losing the treasure by spending it or letting a monkey steal it from you will not help.
This shouldn't be attempted until you've beaten the game a few times so that you're very familiar with the gameplay, items, and levels. There are two factors which make this the highest-ratio achievement in the game:
1. Because you can never buy items, you'll necessarily be less well-equipped if you're attempting a Low Scorer run. You're limited to what you find along the way.
2. It's easy to pick up gold without noticing it. Although gems are large and conspicuous, gold ingots are fairly small and can be hidden behind the decorative bits in the level. Gold nuggets can sometimes be found inside tiles and are nearly impossible to see.
Here are some tips for each area:
* Explore as much as you can. There are no foreground elements that can obscure gold ingots, and you aren't losing much time if you do accidentally pick up some and have to start over. Whip gold and gems out of your way if you have to.
* Get as many crates as you can. If you have at least four ropes left and can trade one to reach a crate, do it! There may be more ropes in there.
* Go for the Mattock if you get a "snakes" event. Get to the bottom of the pit, whip the rubies all the way to the right, and place a bomb one space to the right of the Mattock. You should be able to pick it up and get out without any gold.
* Sacrifice a damsel to Kali if you get the chance. This is your best shot at getting a helpful item like the Compass, Climbing Gloves, or Cape.
* Try to get the Udjet Eye. There are sometimes valuable items in the walls, and you will also be able to avoid bombing out gems if you make a shortcut.
* Watch out for gold ingots on top of trees; the leaves obscure them. Use your whip to flush them out before you walk over the center space. Everywhere else, the ingots are plainly visible.
* Check for crates in pools of water.
* Exploding frogs may scatter gold nuggets from the terrain. If you see evidence of an explosion, be careful!
* If you get the "dead are restless" event, check for the ASH tombstone with a shotgun underneath. And look for vampires; you can take their cape after killing them.
* Hurry through this area the most quickly. Aliens and mines can destroy terrain and loose tiny gold nuggets. It's not worth exploring.
* If you've gotten this far, there is more danger from dying than accidentally picking up gold. However, be careful passing behind decorative columns which may obscure gold ingots.
* Luckily, Olmec crushes most treasure beneath him. But if the terrain is uneven, some of it may be left. Pay close attention. You may want to use a larger, shallower pit. It depends a lot on which items and how many ropes you have left at this point.
Lastly, if you've had a hard time, don't give up! You might get lucky and find a jetpack in a crate early on.