If you want to begin selling digital images, you would likely want to ask a few questions of the buyer before making any decisions on output or price. Some questions I would recommend include:

• Is the image for personal, commercial, or non-profit use?
• If the image is for commercial or non-profit, who is the intended audience and scope/scale of the audience?
• What is the desired output? (Digital display only, 4x6, billboard, website header, etc.)
• If the image is for commercial or non-profit, what is the duration of usage (1 month, 1 year, etc.)?
• If the image is for commercial or non-profit, do they need to modify or alter the image in any way?

These questions will help you narrow in on an appropriate price as well as create a license that makes sense for the sale. Some people would suggest that having attribution on a commercial on non-profit sale would alter the price; I would strongly suggest against that unless you are confident that it will result in later sales.

At any rate, it is highly unlikely that it would make sense for you to share the RAW and even less likely that you should share the XMP sidecar. Literally no one would ever want your sidecar file as part of a sale. I wouldn't recommend sharing the RAW file unless you are paid very well for doing so and you are certain that the license agreement you have in place is desirable for you based on the fee you are collecting.

Of course this is getting into the business of photography, of which you should probably pick up a book on if you are really going to take it seriously. The quick method without getting complex would be to pick up quoting software such as FotoQuote (link).