Love what Leahs Lovely Lops said!
The idea of treating it like a business is key. We have made money on our rabbits, enough to pay for more rabbits and all that they require. Its been good! But we also show and work to improve our lines, and started with Holland Lops (which is what we are known for). We now have Calis, Giant Chins, and Lionheads too. The best source of advertising for me has been facebook. I created a business facebook page, South Texas Holland Lops and do updates when new litters are born. This keeps things fresh in my customers minds and then they flock to me for bunnies! I have only had to advertise on Craigslist once this year I believe, for an older doe (they are always the toughest to sell as most want babies). Mine all sell for $50 for pet quality, $100 for pedigreed/show quality. And we are just now building our show line so we have yet to try out the $100 price margin. No one in our area sells BEW Hollands, so we are setting up for that next year too (now is summer break so we are acquiring stock).
We have business cards, set goals for our business, track income and expenses (just starting that and its tough but I know it will pay off in the end), and always send off our bunnies with some feed and info on how to care for them.