If the entry fee is $100 - and they only had 10 teams - that is only $1000 to run the contest. If you pay for a space to have the contest, some type of shelter for the judges, buy the clamshells, judging sheets, water for judges, rent tables, etc. you can easily outstrip that. I think it depends on what you are out to do. I say do it.... but as you will see, I am a BBQ hoe. Our cheapest contest is Greeley KS - it is $50 entry, and has a "buck a bone" component that goes to benefit the local charity there of your choice... Town and Country, the shelter, the School, the volunt. fire dept., etc.
They have ALOT of community involvement... so they get money for thier charities, and they get alot of prize money donated from local businesses. I have made $600 in prizes and gotten a reserve grand there. ( 30 teams usually)
I organize a contest in the winter in Melvern Lake. We charge $100 as well. All entry fees minus the cost of the site, etc. go to prize money. We get some things like Tel-Tru thermometers, knife sets, spices, etc. donated and use those for door prizes or additional place prizes. No ribbons or trophies... that would eat cash. Cash and braggin' rights is all we leave with. For example. We did a Dead A$$ Last award as well.
I think $100 is fair -- prizes are largely determined by # of sponsors donating money or product... and by the overhead of the contest.
Cook that sucker and get yourself some braggin rights. sometimes, beating your neighbor in the church parking lot is better than any amount of money.
I can think of a couple folks I love to go head to head with, and pick a contest just so one of us will have bragging rights til the next bout.