Yes, you can definitely make a profit as a free account (FACC) or premium solo Paladin in the 150-200 level range. For FACC players, since Yalahar is now accessible, you can farm Imbuements as one method, though I imagine you're asking about making a profit while leveling up.
It is definitely possible, but it will rely on your skills, luck, and how effectively you can play the game. For example, you can try farming Grim Reapers, killing them one by one with Fire Walls while being cautious, or you could try hunting Nightmares on the surface of Yalahar. These methods should help you make a profit.
If you're a premium account (PACC) player, you have more options. For instance, you could go to places like the Chosen or other areas where you can use Fire Wall to take down enemies one at a time. There are many guides available for PACC players that offer helpful tips on how to make a profit while leveling.
For FACC, your best option is probably sticking to the Grim Reapers or Nightmares, as those are more reliable methods to make money while leveling.