Welcome to the board, Spottedsharklove!
Do you have a local party store with lots of party items?
What about the local Dollar Tree store? Everything is $1.00 or less and they have lots of neat items for party bags, matching plates/napkins/cups/plastic tablecloths/plastic silverware. Party hats, party horns, simple decorations, party bags, & plenty of items to place in the party bags.
Themes could be "Cars" (the movie) (this was a big one for Valentine's Day last month),
Blues Clues,
Thomas the Train,
Scooby Doo,
BigBird,
Winnie the Pooh,
Hot Wheels cars,
Tonka Trucks,
Firetrucks,
Finding Nemo,
Sponge Bob Squarepants,
Batman,
Spiderman,
Superman,
or just Happy Birthday.
Those seem to be the top favorites.
Even your local Walmart can make a theme cake,
ice cream,
party favors & paper products
drinks, etc.
There is a big party store online, which I can not think of at this late hour.
Someone else will probably post it for you!