think i got hosed !

Just bought a 96 camaro rs convertable with 104k miles. Went to get inspected and it failed. Codes p0154,p0300,p0441 and found out check engine light was unscrewd. Car looks mint and I hope this isnt gonna cost me big bucks. I know this is alot to ask but based on the codes can anyone give me a worst case amount to fix. Thanks for any help.

Where did you buy it from? If it was a dealer can't you take it back? If it was someone else you can take them to court for whatever it costs you to fix it...

P0154 - O2 Sensor Circuit No Activity Detected (Bank 2 Sensor 1)

P0300 - Random/Multiple Cylinder Misfire Detected

P0441 - Evaporative Emission Control System Incorrect Purge Flow