First snort's free.

When did we get so cheap that we lost the art of 'try it before you buy it?'
As marketeers, we could learn a lot from the drug dealers.
If you have a product or service that you believe has market value, factor into your marketing plans the freebies.
1. We like free things.
2. We are more likely to give you some money if we feel the ROI.

Whether your peddling mandarin chicken or ad campaigns, be like the guy with the toothpicks at the mall food court.
Let your prospective buyer sample the goods. Auto dealers have test-drives, clothiers have fitting rooms, why can't agencies let their clients try on a campaign to see if they like.

Now before you jump to... 'We do, it's called spec work.' That's not what I mean.
I really see a more tangible hit. Give them a lil' bit of something that they can actually use to prove your point. And don't forget all the others that are interested in you making the sale. Your suppliers should also be willing to play out a few freebies to grease the skids.

This is not intended to tell you something you don't know. Just a reminder that you would never buy a shirt-- from the 3 presented to you mounted on black boards-- without trying it on.

We should all want the same thing, a mutually beneficial relationship that helps grow our businesses.