Shopping with style
Usually, the cheapest way to buy gear for your character is the Auction House. Every time you level up, go back and check the Auction House to see what new gear you are now capable of using. The easiest way is to browse the Armor or Weapons categories by level, scroll to the bottom and see which item names are written in yellow letters, indicating that you are able to equip it.
There aren't many worthwhile accessories at these low levels, so focus on good armor and weapons. The exception are mages, who have access to some good rings at level 10 - Black Mages will want to buy rings that boost INT, White Mages will want to buy rings that enhance MND and Red Mages can make good use of either.
Mages will also want to frequently check the Scrolls category of the Auction House. This is where they can buy scrolls from which to learn spells. As with equipment, any usable ones will be indicated with bright yellow letters.
Cashing out in Conquest
Once you've reached level 10, you should have accumulated a fair number of Conquest Points. To see how many you have, open the game's menu, select Region Map, and check the number in the lower right-hand corner.
At level 10, you'll be able to equip the Rank 1 Conquest items from your nation, but that will occur later. More immediately useful are two rings that boost the experience points you gain once a day, from monsters. Once you have 1000 Conquest Points, head to your nation's Conquest representative, select "I want to spend my Conquest Points," choose "Common Items" and select the Empress Band near the bottom of the list. Equip the ring and then use it from your inventory when the letters turn blue. For three hours you'll receive 50% more experience points free, up to 1000 points total. Each ring has seven charges and can be used every 16 hours, but you can only purchase one per real-life week.
Other useful common items are the Scroll of Instant Warp, which will instantly return you to your Home Point back in town, and the Scroll of Instant Reraise, which will let you rise from the dead once after you've used it. Provided you accrue enough Conquest Points, buying and reselling Rank 1 Conquest gear can be profitable or just save you money on your next purchase.