Your question strikes me as a little odd because you've been on the forum for a couple of months now, and it's something you could have figured out for yourself instead of waiting for someone to hand it to you on a silver platter. But I've looked at your post history and I see that you were mining. Why do you want to buy bitcoin? Is it because your miner broke down? Or because it's not profitable for you? (I imagine you were mining altcoins, which you could swap for bitcoin.)

By the way, I've noticed that you're using the forum responsibly, and I've chosen one of your posts to give you a merit for. It's a shame I can't help you with what you asked about in it.