Build your character as you climb.
Check MP for Cheap items that give good results
... example: Level 40 Plate with 75EE (70fg) vs Level 45 Plate with 35EE (65fg)...
... the 40 Plate will have more defense than the 45... so that armor will help you from level 40 to level 50
Check your equipment by 'welling' at your characters level
... example: @lvl15... try to 'Well' TierIII & TierIV items... if you succeed with above 85%... this is a good setup
... once you start getting higher... you will notice the difference in welling and your equipment... certain things will need to be upgraded
... to enhance your survival rate
Once you have found/bought your upgraded items... sell off the other items around the same price you bought it for (or more) to get your funds back
This is the only way with minimal budget to improve your character.
Also... if you see an item that is good... but is semi high in price... wait till the next day... see if it comes down in price... sometimes it takes a bit longer