See Page 72 of the KOTOR Saga edition book.
Energy Shields Come in 3 Varieties: light, medium, and heavy
A character with an active personal shield without the corresponding armor proficiency takes a -5 penalty to their reflex save and is denied their Dexterity bonus. They still gain the benefit of the shields. The shields armor penalties and maximum dex bonus attributes only apply while the shield is active.
Light Shields; Cost
SR 5; 500
SR 10; 2000
Medium Shields; Cost
SR 15; 4500
SR 20; 8000
Heavy Shields; Cost
SR 25; 12,500
SR 30; 18,000