Marketplace seller and ways to advertise on BHW, can someone explain more about this?

What benefits you get if you are Marketplace seller?

and how to can pay BHW to advertise your services more?

You are a Jr VIP already, you don't need a marketplace account. As a marketplace seller you can make a thread where you will be selling your services. But as a Jr VIP you can do the same as well. For paying bhw you could contact the mods probably on how to get advertised here. Last but not least you can pay a Jr VIP member to lend you his/hers signature (advertising space).