Well, that's going to depend on what level she is- Supplemental Register (SR is 50%), Foundation Book (FB is 75%) depending on what part of the country you are in can be gotten for $300-$350- Herd book 1 (HB1 same % as 1st Generation ADGA American doe) and Herd Book 2 (HB2 same as 2nd gen. ADGA American doe/1st gen. American buck) from me would be $400- $500, the higher rate if I breed her for you. British won't be available for some time, but I can foresee a $600 price tag. Some breeders already have British level, but won't have them available for sale for some time as well.
A good doe to start with is the FB level, since she will throw HB1 kids-
You can also take your ADGA registered Swiss eared does (only)- Saanen, Togg, Alpine- to a purebred Golden Guernsey or 2nd gen. British Guernsey buck for breeding and begin your own Guernsey herd. Try to use a doe with a VERY GOOD or EXCELLENT LA score.
To do that, first, do the breeding. Then, if she throws a doe kid(s), you will register the kids with the British Goat Society, as well as the dam of the kids. BGS has an Identification Register, much the same as the Recorded Grade ADGA has. If you get lucky and get doe kids, you will have to join the BGS, register a herd prefix and get a herd ID# from the EU, which is tattooed in their right ear. Don't worry about your ADGA doe, this won't affect her at all, except on paper. BGS is a bit more pricey than ADGA, but if you keep it small, it won't break you!!!
There are bucks available all over the country- I have two purebred GG bucks, one British level buck and one HB2 buck. Stud fees run in the neighborhood of $100 a doe, pretty much the same guidelines that ADGA has for breeding and re-breeding, etc. There are also bucks in GA, OH, IN, WA, OR, WI, PA, NY and other states. You'd need to contact their owners to see if they accept outside does for service.
Semen is also available- 5/$250 on many of them from Nina Schafer/Anin's dairy goats- she ALWAYS goes to the ADGA convention and does a collection tour across country afterwards, so domestic and imported purebred GG semen can be gotten then as well. Be aware that imported semen is EXPENSIVE ($125 straw), but not so much that it is more than say a straw of HAC Whintin (Togg), or AA Victor (Saanen), or many other stellar bucks out there.
I encourage anyone who is interested in beginning a Guernsey herd to join
GGoats@yahoogroups.com and take advantage of the fellowship PLUS the files section which has many important documents for printout so you can learn as you go. Really, we do not bite!