Hi Sue
As a buyer I expect, to get my money back within 2-3 years.
With an empty mare like FDL, that basically means you need to work out what her first foal will bring. Depending on type etc, you would say 75-100K. From this you then need to deduct the service fee and breeding costs etc.
The balance is basically what I would say she is worth. so prob around 60-70K. A seller would probably want more!
Hope this helps.
Regards
Harvey