The whole breeder vs. pet shops debate confounds me. It depends entirely on the breeder and the pet store in question. There are good pet stores and bad breeders...in case anyone forgot.
Pet stores also have the benefit of allowing you to handle and play with your new pet before paying for it, and being close to home allowing you access after the fact to any knowledge they may have. As well...you avoid shipping charges.
So while you might pay $50 for a normal corn from a pet shop, you don't spend $50 on shipping. A normal corn from a breeder online might only cost you $25, but you pay $50-60 in shipping, and that normal corn just cost you $75-80, sight unseen, and having never handled the snake you just purchased. You also have to worry about the shipping, and if the snake survives.
Like I said...depends ENTIRELY upon the breeder and the shop in question...
But back to the original question...when I got my first normal corn for my daughter, we spent roughly $185 for cage, UTH/thermostat, hides, substrate, and water dish...INCLUDING the corn, and we bought it all from a local pet shop where she could go in and play with the corn before we paid for it. As well, you can minimize costs by using cereal dishes for water, and general household "clutter" for hides like TP rolls, plastic containers cut in half, empty boxes, etc...
BTW...that first corn is the nicest corn in my collection, has never hissed or even pulled back into a strike pose, is extremely healthy, and fathered his first clutch this past spring. He is a normal Aztec het. for amel and motley. I regularly use him for educational purposes and bring him to the pre-schools in the area where all the kids are able to hold him and pet him...and he never gets angry or stressed. Pet shop snakes tend to be accustomed to lots of peering eyes and "hands on" experience from inexperienced people. This *can* make them less stressed out over time, and easier to deal with. Noty always...but potentially.