I'm event planner and work with all types of budgets. I'll give some tips for throwing an inexpensive party: 1: make your own invitations: invitations are extremely easy to make. You can make and print them from the computer.
Here are free printables invitations: http://www.greetingsisland.com/Invitatio... 2: hold the party at home: if you're on a budget, the best place to throw a party is at home because it's free and comfortable. 3: keep the decor simple: buy balloons, garlands and maybe some flowers. They will be throwed away after the party, anyway, so keep it cheap.
4: serve inexpensive snacks: mini sandwiches, hot dogs, pasta, popcorn and cookies are low cost. Prepare the food yourself, it's way cheaper. 5: bake the cake by your own: actually, I like to suggest cupcakes instead a big cake, but if the birthday girl want one, baking it at home is cheaper than ordering one.
6: give homemade favors: make homemade chocolates and put inside cellophane bags. (you can put other things instead chocolate such as pens, notebook, lip gloss, stickers and these small things you can buy in dollar stores). Ice cream themed is a cool and cheap idea.
Make an ice cream parlor using 1 or 2 tables. Serve ice cream, banana split, pretzels, waffles, milkshakes. Another inexpensive theme is cupcake party, set up a table to the guest decorate her own cupcakes, have some games to keep the party going.
Get creative. Ask her a theme and plan the party together, after all, it's her party and I think she can put some input, just make it clear that who's coming with the money are you, so the ideas have to be within your pocket.
Laser tag, you can never go wrong. And why don't you plan the party as a mother-daughter team, so she can feel that she is a little more grown up. Also for what to get her, what about a girt card or make-up.