Price for On-line Photo Usage

[moose135]

Received this e-mail today:

Hi Moose,
We'd like to use one of your photos of the New York Air Show on our web site (under development).
http://moose135.smugmug.com/gallery/173 ... 1#90706867
We'd gladly give you credit and link to your SmugMugs account.
What is your rate?
Thanks very much!

Going to their page (The Contrails Group) and sure enough, all you get is the home page with an "under construction" message. Any ideas on what to ask for pricing? Any restrictions I should keep in mind (I won't send a high-res copy for web use, but anything else to keep in mind?)

Here's the photo in question.

[PhilDernerJr]

I would ask for $50 of even $75. Web usage isn't as valuable as print.