The surgery would cost about $250-$500 probably, depending on your vet.
I would not go to that extreme yet though. You mentioned he has a scratch on his eye, and if he has been rubbing that eye, his face could be swollen causing the entropion to be there.
You mentioned in the other topic allergies. Allergies can cause the eyes to swell and water, make them itch. I would first try switching his food. You would much rather find the source of the allergy.
Eukanuba is a 1 star food, full of fillers and who knows what road-kill. I know because I was also feeding Iams myself, (eukanubas partner brand), and THOUGHT I was feeding a good quality food.
Once I switched to a great food- the difference was unbelieveable. I was happy, yet dissapointed in myself for feeding my beloved bullies what I now call "the equivelant of eating nothing but TV dinners and potato chips for humans". You may have to try a few to find the one that is best for your bully. His stools should be firm and solid. Also if the bag says to feed 3-4cups per day, cut that down too. If you bully is a puppy, that may be ok, but if he is an adult, depending on the amount of exercise he gets is how much you should feed.
Remember while switching your dogs food, you must do this over a period of at least 4 days. 1/4 new food, 3/4 old food for 1-2 days. 1/2 and 1/2 for 2 days minimum, then 3/4 new food and 1/4 old food for at least 2 days. Then fully on the new food. It may take up to 2-3 weeks to see the difference in your dogs overall appearance.
Also make sure the treats are grain free as well, and giving frozen baby carrots as a snack (especially in the summer) is something your bully will probably love, and it is good for them.
Here is a link to the dog food ratings: http://www.englishbulldognews.com/DogFoodAnalysis.html
If he is still having problems with entropion once you got his allergies under control, only then would I have the surgurey done.
Did they give drops for the eye and the entropion?