Easiest is to have a great website that people actually want to visit. Ask yourself this, what's in it for them?
You can have traffic tonight if you set-up an adwords campaign on Google. But you probably knew that already...
spend a few hours and post on all of the social bookmarking sites, there are well over a hundred...they're good for free traffic.
Try making some free guides, articles, ebooks available to your readers. You can market yourself as an expert in your business or just get them to come back or refer you to someone else later on. Lamah
I primarily use 2 forms of free advertising for building traffic, those being writing articles and submitting them, and forum posting with a link to my site in my sig.
number of traffic sometimes depend on the kind of site that you have. If your site is full of good contents and useful to reader you can have more traffic to your site. But you need also to optimize your site and your site must rank on major search engine.
get backlinks from keywords and get importance in search rankings. there could be a thousand ways, if you want any specific way, and you want to pay me a few $$, you can always send me pm, and get the best method. [i will give you traffic ideas frist, and then charge you money] anyways, you have already mentioned that you won't want to pay, but how much you can pay will really matter
If it is just traffic, the fastest way to get traffic is through Email Marketing. Send out emails to Groups. The results are instantaneous. Just avoid Spamming.
Well, I guess doing all and every ways proposed in this thread, you should get a couple of thousands uniques in no time
To get more hits and traffic : - Design SE friendly and visitors friendly website - Go for Link building campaign - Go for paid submission in popular directories - Banner advertising on famous portals - Text Advertising on all major search engines - Free information about the services