How to make a present for my mom free?

Pick some flowers and write a heartfelt note expresssing your love. More than enough.

A handmade card or sign saying thank you for everything and I love you is a wonderful thing.

Give her some coupons for special treats for her – like a breakfast in bed or doing the laundry or helping out with a sib. Or bake some cookies or brownies or paint a picture.

Or as others have said, a homemade card with a note is lovely.

As @janbb mentioned. Free chores spread out or do all her chores and spoil her all day. Moms love a free day of doing absolutely nothing and knowing that things are getting done. Depending how old your are and your skills.
Look up a recipe on line and cook her favorite meal.
If you are great at art. Draw her favorite thing or draw a portrait of her and you together.
Draw up a bath for her and give her a pedicure and manicure.

Write a really sweet note where you really tell her how you feel about her as a mom and what are the qualities that makes her special to you. Moms are constantly wondering if we are raising our children right and it nice to feel noticed and appreciated. If you have some sort of photo printing app, on your computer, you can put a picture of her and you together from a moment that was very fun to the both of you and then add your words. Please no, roses are read… or some lame poem. Actually speak your words from your heart.

But most of all. Moms love spending quality time with their kids.

Put together a scrapbook showing your favorite memories of you and your mom and telling her why she is special to you.