Progressive Scan DVD player: $30 (Target, Wal-Mart, Sears)
Telephone wire: $6.99 (Radio Shack, 100' spool)
Old TV $0 to $25 (Thrift Stores, Yard Sales, Your Garage)
Total cost: $36.99 to $72
I'm thinking you could put the DVD player under the driver's seat and use the phone wire to hook the DVD palyer to the TV. (It's cheaper than a portable DVD player) If you're feeling more ambitious, put the IR diodes on another wire and mount them on top of the TV.
Why telephone wire? Because its multiple leads take up less space than typical AV cabling, so its easier to snake through the car.
It pays to be frugal.
