Not to rain on your parade, but 550 users on a game site is still quite small. I'm far more familiar with sites in the USA but I assume the general rules will

Not to rain on your parade, but 550 users on a game site is still quite small. I'm far more familiar with sites in the USA but I assume the general rules will apply. With sites I am familiar with, Google Adwords is usually used until reaching 100,000 users or so. If a site caters to a niche audience then it may be possible to find advertisers/ a sponsorship with far fewer users. Gaming attracts a general audience, however, so I think you would need to grow your user base before reaching out for sponsors. Feel free to reach out to me with any specific questions.