I have a writing and editing services company, and we currently have $4500 of our operating budget. We are planning to do direct mail marketing, advertisements in trade journals, and online marketing (pay-per-click, e-newsletters, etc). How much of my marketing budget should I allocate for online marketing?
You can test how well PPC works for you with a very short test, $100-$200.
I recommend going with Google/Yahoo Paid advertising for it's wider audiences.
Create your most compelling ad copy and target popular keywords in your space.
Implement the conversion tracking code provided by Google / Yahoo on your "thank you" / sales lead page.
You'll be able to determine the ROI of PPC within a short time, and short spend.
Hope this helps!