For me, bitcoin ptc sites such as
http://bitter.io convert quite well for me.
cetobeto.com campaigns seems like a good way to get conversions as well.
easyhits4u.com, traffboost.net, and trafficswirl.com are also great options.
You may also purchase cheap advertising from my sites:
http://www.geekbasic.com/admarket/Right now, you can promote your banner in rotation at the top of my bitcoin PTP sites which have many users for only $0.50/month.