Its what ever they feel like charging. Some people charge the price of what 1 puppy should sell for, while others charge the most they can get. Some say their fee is $2000 so that when they offer the dog at $1000 people think they are getting a deal lol. Each person has their own way of pricing their stud.
it should be the more your dog has proven himself with titles or working degrees ect should reflect the stud fee but thats not always the case , some dogs without any titles and never been shown or worked sitting at $3000 and up , I guess its whatever the person can get. There are some great advertisers out there who are able to hype dog up regardless if they are worth it and people buy into them because of the hype and big productions regarding a certain dog. for a dog with no titles and nothing to prove what he is dont I wouldnt go past $200-$500
Its probably similar to the question that was asked regarding the price of AmBullies: Stud service is worth what people will pay.
* Quality of prior litters & his potency as a stud dog
* Quality of the stud himself
* Probably also factors in whether its a natural breeding offered or shipping semen, which would cost more.
For me, I also look at what the dog has done (titles) and his health-testing scores. But plenty of folks have said they don't give two about it, so.