Thanks for holding!
Unfortunately, there is no easy, 1-answer, "it's this..." type of answer here. So to give an estimate at this time would be impossible. This code is just a "general" code that states there is a large leak in the EVAP (emissions control/recovery) System. The first thing to check here is the Fuel Cap. Make sure the cap is tight and seated correctly. Check the underside of the fuel cap for any cracks or signs of defects that may keep the cap from sealing correctly. If there are any doubts about the inspection of the cap, replace it. Keep in mind, you will need a cap that meets OE Specs. Those "universal" or "locking" fuel caps sold at after market parts stores do not meet OE specs, and will not seal the system correctly.
If the cap is good, then the next course of action is to have the EVAP System "smoked". This is where a machine forces smoke through the system and any leaks can then be found and repaired more easily. The price of this test varies from shop to shop, but the average is roughly $125-$175.
If the smoke test proves no leaks, then the Fuel Tank Pressure Sensor will need to be tested and inspected. This sensor sells for around $65 and the Labor Time Guide calls for 1.8 hours to replace it. Labor rates vary from shop to shop, so what you pay for labor will effect the bot***** *****ne. For a job of this type, a "fair" labor rate can be anywhere from $85-$125 per hour.
Please remember to leave a rating using the 'stars' or click 'Accept'. A 5-star rating is much appreciated! Rating or accepting my answer does not cost you extra.