What is the right price for this service?

[frankpansin]

Hello everybody,

Thank you in advance for your opinion.

I've developed a little marketing tool that is proven
to deliver for my existing clients, roughly between $5,000 and $10,000
a month in revenues.

My direct costs are under $700. Right now I'm charging only 30% as
an "agency fee" So the bill for my clients is $1,000, $700 for marketing and $300 for me.

Now I want to add more accounts and I'd need to hire
a sales rep. But I have no margin...

Would you ask $ as one time sign up fee? How much?
Would you ask $500 or more as a consulting fee?
What do you perceive to be the value of $5K to 10K a month,

I offer no guarantees, the outcome is stable but not guaranteed.

What do you think?

Thanks

Frank