I'm amazed at the number of people who say "just buy a new X" rather then sharpen or repair the old one... I guess we really do live in a consumer society.
A simple sewing kit will set you back around $5-10 at most, that's a few needles, some thread, etc. and it's enough to last you years, It takes maybe 5mins max to fix a hole in a pair of pants, sew a button back on a shirt, repair a sock, and you've got extended life on that item, you don't have to buy a new one, and you've saved money and time if you were going to make a trip just to buy that item.
And cooking is cheaper then buying fast food, I know it doesn't seem like it, but for $10 I can make enough food to feed me for 4/5 meals if I really wanted, good meals at that, that's what? One trip to KFC? It's also better for you generally.
Every now and then I do a "cooking day" when I make up a half dozen dishes, simple stuff, and pack it away in the freezer, usually sets me back around $50, and when I'm feeling lazy out comes the stir-fry I cooked last month or the chilli or the fried rice, and into the oven it goes.
The knife thing is even more about saving money, a decent set of knives if $50-60, and if you take care of them they will last you years, replacing them all the time is going to cost you a lot of money and "it's sharp enough to cut" comments... well I hope you like blood loss, a dull knife is actually more dangerous to you then a sharp one, chances are much higher it will slip when cutting, slicing, or dicing.
I guess I really must be a high-tech hick, I skin an animal, and build a computer with the same proficiency.