How do I reply to a potential postdoc supervisor who has no funds at this time for me? I am in the process of contacting potential supervisors for a postdoc position, and I need a bit of advice on how to reply to one of them. I have a PhD in urban planning, and I am applying to some American Universities for a postdoctoral position.

After contacting a supervisor, I got a positive reply, however he wrote to me: "You have impressive credentials, and I'm sure you could contribute  to our group. However, I have no additional funds at this point to support a postdoctoral position. I would be happy to talk if you have funding from another source. But at this point, my funding has been allocated to ongoing students. I am sorry that I do not have better news."

What and how should I reply? On one hand having some financial support is quite vital to me, but on the other hand I don't want to lose this opportunity. I would like to show how much enthusiasm I have to work in his group. I would like to suggest to write a proposal in order to give a grant, or asking him if he know somewhere I can find a financial scholarship. Or I ask him to let me know when he has a vacant position for me. I am unsure what to do!
You have pretty much answered your own question.  

In a reply, consider including the following:


thanking the professor for his reply.
state that you would be most interested in contributing to the group should a position open up - even mention a specific common aspect of the research.
ask if he knows of scholarships/ similar funding opportunities etc.
suggest co-writing a grant proposal/application (be specific about which grant and what it would be for).
perhaps even state that you would like to collaborate on projects/research in any case.


On that last point - leave the 'door open' for a continuing link through research etc. - this may put you in good stead for future opportunities.