This, and four-thousand other questions along the same lines. I hear these alot. The answer is complicated, and I'll tell you why.
Any handmade item is going to carry a higher price tag than mass produced factory line stuff. Be it jewellery or a messenger bag or a steel chain shirt. In many cases, crafters are doing this on their own. We have both materials cost and our own time and effort to consider when setting a price. My time is valuable to me as I'm sure yours is to you. Time I spend mailling for somone else is time I could spend playing guitar or annoying my cats. Difference being, mailling is work. When most people work they expect to be paid X per hour for dedicating their time to someone else's venture.
So the understanding is, I am making an hourly wage. Most skilled tradesmen scoff at the proposal of taking a project on at minimum wage, and crafters should be no different. We employ a skill and talent that is trained and personalized, and therefor valuable in itself. We shouldn't be made to feel bad about considering our crafting time as valuable as that of a carpenter or welder.
In maille, buyers see finished sheets or chains of rings, maillers see the wire that was wound to make the coil that was then cut to make rings. We see closing each ring individually, and some to all of them have to be opened first. This is work, it's tedious, mind-numbing, and time-consuming. There's time again. Do you expect a product you buy to be made well, not have flaws, or pinch and stab you. This is what you're getting when you purchase a handmade item. There is a distinct difference between handmade, and homemade.
And the idea of handmade comes back around. People who craft handmade anything will generally attempt to use materials from local sources whenever possible. Local can be the shop up the street but it also can mean your own country. The idea of outsourced labour and imported materials is enough to start a riot in some parts of America. Buy handmade and you're pretty much guaranteed to be buying local, and you can feel confident that the money the seller allocates to his personal use will be spent locally. Would you rather spend 20$ in some random foreign factory, or 50$ next door?
There's at least one popular site selling pre-made maille shirts for an inconceivably low price in my mind. I don't know where they get their wire or rings, how their maille fabric is woven, or anything about the quality of their closures. It's obvious from the price tag alone that these items are mass produced. I can almost promise if I were to call them, they couldn't tell me exactly how it was made or where the rings came from. Nor can they tailor it specifically for an individual.
So, how much for a shirt again? That'll depend too on your measurements if you want it to fit properly. Then we have to decide on a material and the grade of the ring cuts. If you're expecting saw cut stainless, expect to write a cheque with more than two zeros on it, there's no way around it, the time and effort in saw cutting rings alone is worth several times more than the 100$ I've heard offered for a hauberk. In "low end" galvanized steel cut by a ring making machine or by hand with bolt cutters, you're still getting an incredible deal if you only pay 3-400$
So give it some thought the next time you find a handmade item of any sort and gawk at the price tag when "you can go down to Evil-Mart and get one for half that." You're not getting the same thing by a long shot, and if there's any question about the work put into it, any crafter will be more than pleased to tell you about the work put into an item. Ask with a genuine interest in how it was made, not so you can find a way to talk down the price, we can tell the difference. ;>
Have the fun