You quit GIVING illegals money, food, healthcare, housing, phones, etc....and like you said, fines and jail time.
As for cheap labor....we have the world's largest inmate population....you put the non-violent ones to WORK so they can PAY THEIR DEBT TO SOCIETY......unlike the powered-butt baby-sitting they get now. They don't need, weight rooms, soccer fields, basketball courts, etc.....they need to WORK and WORK HARD....learn a skill and be educated in some way. But no frills or fun.....they aren't in timeout for not taking out the trash, scratching the car, talking back to a parent, or chewing gum in study hall....they broke the law. This is where plenty of cheap labor can be found.....cheaper than even hiring illegals. Not only would we save BILLIONS from illegals leaving our country, we would save by able bodied prisoners working to offset so much of our tax money having to go to prisons.
And for the ones doing life or on death row for murder.....time to send em to their Creator.