How Much Equity to Offer First Employee?
SriniCenthala: Hi ,First find out your company's worth not just by the investment, 
1. go by your time & Effort & convert that into your investment amount, 
2. if you market it successfully assume it is successful. Identify the worth in terms of moneyAs you have mentioned that 20% for employees , that's good at least you have decided already.In your situation , for the employee irrespective of part time or full time , determine the effort & work accomplished equivalent in the market. Based on that provide the equity for the resource. 
Usually Sales commissions are ranging from 2% to 15% as commission from the revenue generated out of that deal.
Fix a base salary which is something like 50k if it is full time. And add the additional commissions of what ever the percentage you decide.If you can't provide the base salary then think about provide equivalent equity in percentage terms with the condition of being with the company for at least 2-4 years.Be aware that when you want to grow big , you need to go for real investors. You need to provide them big junk of equity.
This is what I do. But feel free to contact me if you have some more guidance.Thanks,
Srini Centhala,
srini@absolut-e.comMy Blog http://Srinicenthala.blogspot.com
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