Prison is not an option. Not that it's not deserved, but because our prisons don't have room for even 1% of the illegals in this country. Besides, that would mean that we taxpayers would again have to subsidize the illegals.
I think a better solution would be to:
1. Sieze all money transfers sent out of this country by illegals. That money should be used solely for securing the borders and enforcing immigration law.
2. Deport all illegals to the capital city of the country from which they came. They should be bussed directly from the airport to the seat of that country's and dropped at its steps.
3. Levy a fine against the government of origin for each illegal we capture and deport. The fine should consist of two parts: the actual expenses for the capture and deportation, and a punative amount.