I was unhappy with the two pellet choices available to me. The rabbits didn't like the Shur-gain pellets and so wasted a lot and I found out that the Purina pellets contained animal tallow, which I do not consider appropriate for herbivores. (This may have changed... It was years ago.)
I was already supplementing the pellets with healthy weeds from spring until fall, so it was an easy matter to start feeding them more of those and alfalfa hay as well. I found they were happier if they also got small amounts of grain. Given natural foods they soon lost interest in the pellets. That last bag seemed to last forever.
Rabbits on a natural diet grow out more slowly than rabbits on pellets, but the overall cost per pound of meat was, for me, about half what it was on pellets. A good source of alfalfa hay is important if you are contemplating natural feeding. Here I can get it for about $3.50 a small square bale...Much cheaper than pellets.
Recently I have been experimenting with sprouting grain, especially in winter. Since you get far more nutrition and weight with sprouts or fodder, it is a very economical way of feeding rabbits.
We have a whole forum for discussing natural feeding and it may interest you to read there for more details. Natural feeding has really caught on in the past five years or so and we are gradually retrieving information about it that was nearly lost during the second half of the 20th Century.
Edited to add: Rabbits on a natural diet need to have access to a trace mineral salt block. I buy the reddish-brown ones for general livestock. They weigh 2 kg. and cost about $3. If your rabbits are in cages, you can knock chunks off with a hammer and serve it in small crocks.
