To encourage your kid avoid the usual white bed sheet with holes for the arms, eyes, and mouth costume.
This is not a great idea, unless your kid wants that. But as someone who has been around, try to be more creative and spend time on your kid’s costume.
Try to remember that nowadays, its okay to have costumes of celebrities and superheroes. In fact your kid might be badgering you of a batman costume. That one can be tricky but with the right materials you can make one from a black cloth, ski mask, kid’s tights, and that pair of boots your kid has in your room.
Other costume ideas include a cat or kitten costume which involves leggings, sweatshirts, stockings or rope for the tail, and probably a paper at mask. A devil costume is also quite easy to make. Clothe your kid in all red or black and buy that head band horns which you can practically see everywhere during this time of the year. You can add a cape if you want and of course a forked staff. Just make sure your kid knows that the staff is for props only and not for poking his neighbor.
Materials you will need for your budget Halloween costumes are readily available in most shops or most of them you can even find in your own home. Again, you can create a great costume while working on a budget, all you need is time to spend and imagination to burn.