If they want to limit the number they pay for then they can have the A standard at 2:15 or so. Then set a number that they feel they can manage for the race (150?) So you pay the way for all A standard guys(say 20 or so) then have a descending order list and take the top 100 marathon times and top 30 half times from the list. Those 130 guys pay their own way and a small entry fee. Here is you chance to use that logo that is being fought for. Have a local sponsor pay the entry fee to have the logo on the singlet, or travel, ect..depending on what that individual works out with sponsoring company. Most marathons charge a fee anyway.
So we have 200-300 guys training hard and racing hard to get on the list. I bet the cut-off time would be under 2:18 anyway.
You also have local Joey Chestnut who runs a 2:23 at the beginning of the period and is on "The List"." Local press can run with the story how Joey C has put himself in position to make the trials. Builds that local interest. Now getting to the deadline, you have 20 guys at the bottom of the list hoping to hang on. Again, local press writes article or local running club send out newsletter saying "follow the xxx and xxx marathons this week to see if Local Yokel can keep his spot" or something similar.
Builds interest, raises bar naturally or in a way that the cream rises to the top and the A standard secures that the right guys are there and do not have to worry about a spot. Is the guy who raced hard right before the cut-off to get the last spot at a disadvantage at the trials, yeah so what. The sub 2:15 guys are the only ones with a legit shot to make the team anyway.