In my view, the financial cost is negligible. Mostly, it's the investment of time, effort, and creating some competence.
At first, I thought this comment might be "flippant", but I now think it is true. If you are the type of shooter who still has shells left in the box that you bought last fall, is not likely that you will ever "break even" by spending any amount of money on reloading gear, and your time to learn, and the mistakes that you will make, and the "competence" that you will gain to load for your rifle, safely. Some of us expend 30 to 50 rounds (or more!) just to find a "best" loading recipe for our rifle - sounds absurd, I am sure, to a 5 round per year shooter. Add in to that mix that today is sort of difficult to actually find to buy the primers, powder and bullets that you might want to use.
If dollars are a big concern - consider that primers come in trays of 100 - so like $10 to $12 these days - even if you only want to use 5 of them. Powder is usually in one pound jugs - so, say $90 per pound - is 7,000 grains - even if you only intend to use 5 x 45 grains - going to have to buy that full pound. Bullets - typically $45 to $90 (?) or so for box of 100 these days. So you are likely going to lay out $12 + $90 + $45 = $147 - even if you only intend to load 5 rounds. (Substitute prices that you will pay, if different than around here.) Some that are new-to-the-reloading-game do not get that. As recently happened here, will find out that many hundreds of dollars of reloading stuff do not do much for the potential reloader, if he does not have the specific shell holder for the press, for that specific cartridge. Except for what is consumed on firing - most of that stuff can be sold later - to recover at least some of the initial cost - if that person decides reloading is not for them.
Was also a question why home hand loader can not simply duplicate what factories do - factory shells seem to work in all rifles. Mainly, they use pressure test machines which most all home hand loaders do not have access to - they know, fairly accurately, what amount of psi those loads will produce from a SAAMI spec chamber. Then, they typically use powders in very large quantities - like in tons - that they blend or add additives to - is NOT usually the same powder, at all, that you buy one pound at a time, at the store.