I believe your best bet to enjoy the game is getting a Premium Account which you can get the neccesary tibia coins by looting several items in free zones to sell in the market, the best options I've tried are the following:
>Gloom Wolf: There are two main respawns, 1)Poacher Caves (Not active every day) and Tainted Caves. In both respawns your target item is the Gloom Wolf Fur which is highly valuable in most game servers. Generally speaking, Poacher Caves is a better respawn but highly contested at least in my server while Tainted Caves tend to be available most of the time, as a tip you can run this respawn with a stealth ring to focus on killing gloom wolfs.
>Forest Fury Camp: You will focus on killing Forest Furys to drop Elven Hooves, here you can also use a stealth ring to avoid being detected by all creatures in the respawn.
>Orc Fortress: Here you will bring (again) your stealth ring and run the respawn killing only Orc Shamans to drop Broken Shamanic Staffs
>Mutated Tigers: Located in the zoo quarter in Yalahar (you will need to get access), be careful and bring a lot of mana potions, your target item here will be the sabretooth.
These are the places that I've found give the most profit, there are other options like amazon camp and yalahar cults but they are almost always full.
As a last recommendation you can do the daily task of gathering Lucky Charms to have the change to get the highly sought after Hunting Horn (This is how I got my first Premium Account like 10 years ago lol)
I hope this helps, cya.