I agree that consumables are better than knick-knacks, unless you know the person will like and use a particular items. At Christmas time, stuff that doesn't go bad quickly is a good idea, because people can overwhelmed with edibles during that season.
Flavoured salt would be good, particularly if you add instructions for use for particular flavours (popcorn seasoning, or using it to rim glasses for drinks, or for fried foods, etc).
You can make up packets of mulling spices that can be used for making mulled wine or apple juice (eg. cinnamon sticks, cloves, dried orange and lemon peel, dried cranberries) with instructions, or something similar for homemade chai tea (cardamon, black pepper, cinnamon, cloves, ginger). If you want to be fancier, make an infused spiced syrup that can be added to tea, by steeping spices and cooking them up into a syrup with sugar. This sort of gift is good for someone who likes food but isn't much of a cook.
For a consumable non-food item, I find cards quite useful. My sister does lovely flower photo cards, and I use them as thank-you or birthday cards. So if you're artistic or good at photography, you can make up sets of cards.
Bath/cosmetic items have the same caveats as buying (allergies and personal preferences). I've seen instructions for home-made bath bombs which look pretty cool, and salt or sugar scrubs are extremely inexpensive to make compared to what is charged in the store. Include a list of ingredients for allergies.
I find that things like jams and jellies aren't necessarily all that cheap, unless you already have canning equipment, and you have access to free or very cheap fruit. If you have to buy good quality fruit to make it with, it'll cost as much or more as a good quality jam at the store.
For other food items that aren't too expensive but keep a while and taste better than store bought - for someone who likes breakfast, give them a pack of home-made granola, particularly if you have access to a bulk foods section to keep the cost of ingredients down. I've got a couple of amazingly good granola recipes if you want them - they keep at least 2-3 weeks in a sealed container (holiday spice flavour, and cranberry lemon almond flavour). Homemade hot sauce is quite easy to make, and keeps for months - for home use, I do a green chile vodka lime one, and a roasted hot pepper one.