Hi and welcome to HC
You can make lots of homemade DIY toys out of cardboard and toilet roll tubes, have a look on YouTube and in the DIY section of the forum for ideas. I'm not sure if this is available for you, but you could always use child's play sand (like what you would put in a sandpit for a child). If not you could always see if you could order some sand online, make sure it's sand not dust though as dust can cause respiratory problems. As they are treats I'd give them occasionally, for example I give my hamsters treats as a reward when I'm taming them or after they have been out the cage if they've been good. You can give them things like sunflower and pumpkin seeds as well as things like mealworms as treats too, they have less sugar in. I have a hybrid dwarf who is prone to diabetes, so if I give him a hamster treat I snap it and give him a tiny piece, or I give him a seed instead. Wheat does contain sugars, it depends what you're using though, for example if you wanted to feed your hamster a piece of bread or pasta try to feed them the brown varieties in as they have less refined sugar in them than white.