Interesting. I'm far from elite, but I've always been able to get into races for free. I moved to a new area and that has largely gone away. The local RDs have a different philosophy.
IMHO, if you're going to offer prize money, you should have a comp standard. The whole point of prize money is to incentivize competition, right? Otherwise why have it? If your prize dollars are less than your entry fees, that incentive isn't there and you're pretty much just a fun run.
I saw incentivization work at a local race a few years back. The RD wanted to see sub-15 on his 5k course, so he offered $400 for first place. All he'd get was local weekend warriors take his money year after year in 15:30-15:40. Nobody from the big city 90 minutes away wanted to make the trip for an all-or-nothing race, even for $400. I suggested he split the prize money between 1st, 2nd, and 3rd and he'd get his sub-15.
Lo and behold, the next year guys started making the drive. Now the race is routinely won in 14:40-14:50 by guys who run 14:00-14:30 on the track. (he also gives out a lot of comps)