I've found it just really depends.
Some factors include:
-Price (How much you are selling them for)
-Location
-How you advertise
-Demand (If others are looking for the breed)
-Supply (If there are already a lot of suppliers of the breed)
Location is a huge factor. I live where rabbits are in high demand and there are no rabbit shelters near. I am the only one within a 3 hour drive in any direction that I know of who raises/breeds Dutch. So those who are seeking Dutch in my area often find their way to my rabbitry. (I personally have never had a problem selling rabbits, and even take in free rabbits who people need gone quickly, and resell them to the best home I can find.)
If there are a lot of people selling a certain breed in your area it may be harder to sell, if others have a lower price etc.
I've found that raising my price has eliminated unwanted buyers. For example, I started out $25 each, and had to weed through uncommitted people. I have since then raised the price to $35 a kit, which has helped to gain the interest of only serious buyers.
I have a website, but craigslist is my main source of rabbit ad sales. If you are posting on craigslist, or anywhere for that matter, a very important part is to make sure you have good quality pictures of the rabbit or rabbits you are trying to sell. This is a key factor! If you just have "Text for pictures" a lot of people will find it not worth the time and waiting, and will move on to other posts, or even blurry or unfocused pictures can throw people off. Good pictures are important, as well as quick contact.