I would say about the absolute cheapest you could get a heifer to calving would be at least $1000, that's developing her on grass and very little feed, only doing a Lute shot and breeding her, assuming no calving problems, and is a completely unrealistic number in this forum lol.
On our show heifers, the feed usually runs us about $1200 (we grind our own) to get one to 2 years old not including show expenses or the purchase price of a heifer. We run heifers with our herd bull (we lucked up and got an AI quality bull for $2000 as a 2 year old)