I am willing to pay, what sites are the best to advertise on to promote my forum
You can always try Google Adwords. One of the most effective advertisement platforms. You just need a thicker pocket to try.
I am also willing to pay for this service.
Please PM meh what you want to advertise . I can advertise on a forum having more than 3,539,592 members registered and more than 1k + active users at a time . And 96 % of 3539592 members active .