ByteBall team is making very aggressive promoting campaign using Bitcointalk Signature campaign: they pay 30-160$ (depends on BTT rank) for every week, but requirements are too high: 25 posts per week.
Well I wouldn't say that it's too much aggressive, it is usual campaign, and it is only signature campaign and they pay on their own currency so they are not spending any bitcoin or any fiat money but the reserved money.
And yeah the rate is good enough and the requirements are not too high, I have seen campaigns that require up to 30-40 posts per week which I would say in that case this is aggressive promoting, at the other side there are campaigns which require only 10 posts or less per week depending on the campaign.
They also are running the twitter campaigns which is very effective and yahoo makes his job just perfect!