2001 Kia Sephia check engine Troubleshooting code P0441

I just had my kia checked to find out a reason for the check engine light coming on. I do have a problem with starting the car immediately after I fill it up with gas. The troubleshooting code is P0441 and it says it is an emission system incorrect purge flow with probable cause of 1. Faulty purge control solenoid, 2. faulty vent solenoid, or 3. Blocked vapor canister. How do I figure out which of these is the problem and fix it the cheapest. Thanks!