You can advertise in your sig, on posts, make posts in the Vendors Promotional Forum (the one right above the rest of the vendors with sub-forums), sell from your stock directly through classifieds/sales/bulk sales. Essentially you can freely operate and conduct business on the website without having to worry about anything. Also you can get included in the weekly emails through various means, and there's a few other 'upgrade' options that will increase your advertising exposure that you can purchase, but if you're just starting I wouldn't worry about those yet tbh. Oh, and you get a cool color for your username
I hope that answered your question, if not please ask away!