Wal-Mart has a $30 tape deck with aux input. You'll also need a casing from there for about $10. Staying with the cheapest way, you can opt to not use a harness and cut/splice wires. Use solder and electrical tape, NOT (removed) connectors. (removed) connectors will fail after a few years.
* 2003 Vibe Auto Satellite Silver w / Moons & Tunes
* Kenwood Excelon KDC-X597
* Polk DB651-Speakers
* Soundproofcow Roadblock R sound deadening in all doors
* Drop In K & N Filter
* NGK Iridium IX Plugs
* 27 MPG City/Highway with AC on