Saturn in third house is a good placement considering it doesn't influence any major houses apart from fifth house. In vedic astrology third house denotes courage and Mars is considered its natural lord. Saturn in third house creates frictions with siblings and neighbours. Native has problems getting his point across at workplace. Native may often have to constantly engage in short term travels for job or study purpose.

     Saturn in third house is good as it limits the bravado and makes a person calculative while taking risk. This ensures long term success. Saturn may make a person a wanderer who has to constantly travel. Aspect on fifth house destroys or slows down the important portfolio's of knowledge gathering, romance and popularity quotient. Relationship with children may see ups and downs and losses in stock markets are possible if native doesn't invest carefully. There can be difficulties conceiving a child especially for females. Aspect on ninth house causes problems on long distance travels and during Masters and Post Grad education. Saturn's aspect leads to unwanted long distance travels. Person's spiritual growth is less. Either he/she blindly follows customs or hates religion altogether. Aspect on twelfth house can lead to foreign travels and foreign residency. There can be financial losses also. 

     Saturn in third house isn't bad if the native is careful in handling siblings, neighbours and co-workers. Natives should stay away from gambling and trade carefully in stock markets. Native should be optimistic as far as possible. Any shortcut route to fame and money should be avoided.