With 81.2 percentile in JEE Main and 78% in 10+2 from Punjab, you can try state engineering colleges like Thapar Institute of Engineering and Technology or PEC Chandigarh for CSE or AI branches. These colleges have decent fees and good reputation. You can also check Guru Nanak Dev Engineering College, Ludhiana, which offers affordable courses. Apply through Punjab state counselling and keep backup options in private colleges with lower fees. Preparing well can help improve your chances too!