There is no such thing as "sweet 13" do nobody can help you
There are loads of good ideas on different sites : google it.
pink and white balloons
gigsalad.com has some great ideas for themes for 50th birthday parties. I think Oriental Trading is the place to look for decorations.
You can find ideas and instructions for handcrafted Christmas decorations on this site (http://familyfun.go.com/christmas/christmas-decorations/christmas-ornaments/). You can make anything from homemade paper stars to candy cane signposts.
Christmas Party Ideas are ideas that are tailored for a Christmas themed party. These ideas can include things like snowman decorations, gingerbread man centerpieces and candy cane party favors.
Good housekeeping and ehow have many ideas with christmas decorations from halloween decorations,Martha stewart also has great ideas for halloween decorations to christmas surprises.
Hats, Plates, Candy, Cups, Stickers, ect. These are some great ideas for a fun time for a Dora birthday party. There is much more ideas online for birthday parties.
A surprise party is a great idea for someone turning fifty. You are never too old for games! Try a dollar store or a department store to find the best suited decorations.
My favorite place to shop for decorations is the dollarstore, its cheap and you can usually get a lot of stuff for you're money. When turning 21 you shouldn't need much decorations. Anything will suit the occasion.
Visit www.HGTV.com. They really have a lot of good and clever ideas for holiday home decorations. They can also provide you with some fun ideas for making decorations for halloween as well.
It is quite easy to find decorations for a 50th Birthday party, and you can find them at local card shops as well as any party supply store. I have found a fantastic site for ideas for your Mom's birthday on this site: 50thbirthdayparty.org/
Depending on what your son is interested in, sports, cars, television , etc., you can use the websites from sports teams, car companies, or tv shows to find ideas for decorations. YouTube is a great resource for ideas as well.