Depends on the business, of course.
We are associated with one site that uses an affiliate program to generate traffic, and a relatively high percentage of traffic comes through the efforts of the affiliates.
And, while print to click is not a high converter, a bit of print here and there can go a long ways - particularly if its "free" print, as in press releases or human interest type stories.
We ran a successful campaign by providing free product to a niche publication that they used in thier own re-subscribe campaign. So, they hit their subscribers with, "First 1000 to renew their subscription get a free widget." We got our widget out there, cheap press and a sustained increase in our customer base and sales.
On the other hand, some stuff that seems like it would work might not. We provided "gifts" for the studio audience of "The View" one time. The immediate increase in sales was hardly measurable, and tapered off quickly. Obviously not our demographic :( (luckily only a cost of a few thousand $$).
We have run successful, targeted discount campaigns using forums. For instance, we offered a 20% discount for a product of interest to US Troops in Iraq/Afghanistan (shipped to an APO address) and promoted it by contacting forum admins for the many sites out there catering to the interests of the troop's families (NOTE: Don't just spam the forums with ads!) Virtually all of the forum admins allowed a thread simply for the asking, but would have been incensed if we had spammed and then asked.
Similarly, niche specific blogs can provide good traffic, but it might cost you a sample or two for them to review.
I would say that if you don't have enough margin built in for a marketing budget, then your long term chances of success are marginal at best.