[Krest]

Don't use these shitty free forums that generates money from the ads they put on your forum. Instead, get a vps or a cheap webhosting then download MyBB from their website and install it manually. That way, you can choose your own themes and not be fucked by ads on your site. There are a lot of free themes, and they look good too.

If you want something that looks "professional", it's not going to come for free. Don't expect everything to arrive at your doorstep for free.