It really depends on how small the budget is, online advertising is pretty cheap compared to offline advertising, you can advertise on Google Adwords for example with $50/month, there are also other ways such as banner ads and text links, plus directory submissions and posting on web hosting related forums which has sections for ads.

The question is, do you have an edge? if your offering the same exact services like others, your gonna have a hard time competing with all of those hosts out there. My suggestion is, find your self an edge, either by coming up with a new service, a new addition to what is currently being offered, or by identified a new market vertical that hasnt been tapped yet.

My 2 cents