Making one yourself is even better.
1. Lightly toast an english muffin split in half.
2. Crack an egg into a small bowl or ramekin with a couple spoons of water and a bit of salt, nuke for 30-45 seconds
3. Spoon out onto the muffin, add a slice of AMURRRICAN cheese, and nuke for 15-30 seconds longer to let it melt, and that's it. Optional: Add ham or a frozen sausage patty or use different cheese to complete the experience.
Total cost is dirt cheap, takes less than 10 (or even 5) minutes and you don't have to go out of your way or wait in line at McD's for breakfast. If you actually wanted to make one that's closer to legit, you could bust out a griddle and do it all there too.
I like the Subway breakfast sandwiches, just withhold the lettuce and all that. I found the steak and egg ones to be decent, especially on a muffin with some chipotle sauce and onions and peppers.