I'm nearing 50 range. Right now I'm killing flesh crawlers using bone bolts.

 

 

 

Once I hit 50 where is a good place to train and what should I use to kill whatever?

Bronze knives at ogres.

or try iron knives at yaks

or try iron knives at yaks

 

i dont want to do any quests.

Steel darts on slayer?

 

 

 

Cheapness and variety.

Addy crossbow + silver bolts are better than bone bolts, hits about the same but with increased accuracy. And silver bolts are only 6 gp each. But knives are very good too.