The rate is $0.25 per ads for 300 ads per days. If going up to 600 ads per days willing to take $0.20 per ads. And if 1000 ads per days, 7 days a week willing to take $0.18 per ads. You wont have to pay anything if the ads is ghost or flagged.
I have done this many times before becomeing a provider in freelancer.com. Everyday at night, will be emailing you all the links to all your ads just to keep you updated everyday. I have over 1000 ips and 2000 accounts, so it shouldn't be a problem keep your ads fresh and non flagged or ghosted.