If you have less money, you can cook them a good meal and make up a lot of auspicious dishes.
You can also find old calendars and newspapers to decorate them on their wedding day.
You can also use their photos to make pottery dolls, which are very similar.
Help them make a wedding photo album and write some touching words so that they can remember it when they are old.
Many, as long as they are related by blood, can see that you are very filial, as long as you use some thoughts, your parents will definitely feel your love.