This achievement will undoubtedly unlock in a regular complete playthrough, and will not require you to go out of your way for it. If you are looking for a quick way to get the achievement, read on.
The fastest way to get this achievement is to sell the cheapest thing in the game, empty shells, to Francis, the wandering merchant (Onion head guy), and then re-buy them from him. Despite this achievement's description, re-buying stuff from Francis also counts. This will result in a net loss of only 4 glim per shell. Repeat the buy/sell cycle until you've re-bought the same empty shells 100 times and the achievement will unlock. Assuming you bought nothing else, it would only cost a total of 400 glim to get this achievement the first time you meet Francis.
If you are starting from the beginning and want to get this achievement as fast as possible, just do the main quests, stopping for crates along the way. You will also have to pick up some empty shells that appear on your boat's hull as you move through the water. You will be able to sell the valuables from the crates to Francis when you meet him for the first time after about 1-2 hours of gameplay, and have more than enough glim to get the achievement right away.
This will also give you progress towards this achievement:
Since you are already here, and probably should have enough spare glim, you might as well sell and re-buy 100 more times for an additional cost of 400 glim to grab this achievement as well.