Are you asking what a traditional publisher spends, or what you would spend if you decide to self-publish it? Either way, I'm sure it's going to be a bunch of "it depends", but for clarity...
that's really how long is a piece of string ... if you are self publishing you could do it for nothing up to the marketing point (not something i'd recommend as it means not using an editor and doing your own covers) but its possible. If you chose to use paid editing and cover designers its still question of who use and what you want - my editor charges £9.50 per 1000 words , but some charge more some charge less (that's for a structural edit - not proof reading) Cover design is another variable - ball park seems to be about £3-400 but you could pay less or more. Then with marketting - facebook ads, amazon ads etc all go for different prices (and that depends on whether you are doing paid advertising at all) and so on In short its not a question that we can answer with any degree of accuracy ETA : actual publishing for a self/indie publisher ought to be free at point of operation but you lose a slice of your royalties - amazon take 30% if you are between $2.99 and $9.99 , outside of that bracket they take 65%.
I wouldn't agree that this is "ought to" in anything like the same way that it "ought to" be free for traditional publishing. If someone decides to publish on actual paper--for example, my understanding is that it's extraordinarily difficult to sell a picture book without publishing it on paper--it's likely to quite legitimately cost plenty. That doesn't mean that every printer is legitimate, but it's not the same "If it costs you anything it's a scam" deal that it is for traditional publishing.
Sure, I should have said "For print on demand the service should have no upfront costs" Print runs are a whole other thing - but except in very specific circumstances (coloring books and picture books are one , extreme erotica/porn which amazon won't list are another ) its generally not a good idea to get a print run for self publishing unless you have a near guaranteed market (like if you are a successful speaker and sell a lot at the back of the room, or you have a lot of preorders for a local interest book) That said even in the realm of print runs there are still shysters, who will charge you several grand for doing not a lot before outsourcing your print run to a third party, who are best avoided