Glad to see you in Mmooffers. The information in Maplestory from the official forum, we just give it a Summary. We sincerely hope it can help you more or less.
Everything that can be sold is potentially profitable, however some things are naturally better sellers than others. We will try to list them according to the amount of mesos(Maple Story Mesos) you have. Of course you can do stuff from a lower category even when you have more mesos. Profit is profit. The following are not price ranges but rather the range you should have in mesos before trying to resell the items listed.
What you should consider reselling with:
Less than 500k. Try to PQ or something to get some money(MapleStory gold). Or you can collect leathers to make Work Gloves, do the Eos Scroll and Orbis Scroll quests everyday, and collect iron pig hooves to make steel plates. Train with a cleric, and so on. 500k. Ores and plates/jewels. A key thing is that jewels and plates often cost less than the ores themselves. This is because most people already have some of the ores themselves, but not enough to make a plate.
Cheap DEF/M.DEF scrolls. If you are in Ludi, people will often be dropping or getting rid of their LMPQ scrolls very cheaply. You can buy a lot by going through the channels and then sell them in your shop for a bit more. Clean work gloves from leathers. Snowshoes that you can buy in El Nath for 28k-30k depending on the job at the armor shop and sell for more in FM.
Thanks for your reading. If you want to level up your charcter, the Maplestory powerleveling service maybe your best choice. We will do our best to help you.