I have Monday qualified several times for Nationwide and PGA Tour events. The process has changed a bit over the past few years as there are Pre-Qualifiers sometimes just to get to the Monday qualifier. The fees are usually pretty high, $200-300 and there are generally four spots for PGA Tour events, and 12 (or so) for Nationwide Tour events. You are generally competing with card carrying Tour players that aren't in the event, mini-tour players, college All-Americans and local studs. The local PGA sections usually run the qualifiers and and it is not unusual for a score in the mid-60's to qualify.
I have Monday qualified several times for Nationwide and PGA Tour events. The process has changed a bit over the past few years as there are Pre-Qualifiers sometimes just to get to the Monday qualifier. The fees are usually pretty high, $200-300 and there are generally four spots for PGA Tour events, and 12 (or so) for Nationwide Tour events. You are generally competing with card carrying Tour players that aren't in the event, mini-tour players, college All-Americans and local studs. The local PGA sections usually run the qualifiers and and it is not unusual for a score in the mid-60's to qualify.
This is in line with what i researched and i think all the PGA Tour Monday Qualifiers have a pre-qual to play in. They were getting too many of the "i want to play with the pros on monday qualifier" people who had no business being out there. Most of the courses you qualify on are generally no where near the difficulty of the actual tournament course which is why most scores are in the mid 60's as ekennedy suggested.
The scores are in the mid 60's because there are more great "sticks" out there than anyone can imagine.