Tipid ideas:
1. If you're holding the party at home and need tables and chairs, check with your friendly neighborhood barangay captain. Ours here in QC lends them to us for free. Or try a nearby church/parish or school.
2. If you're having 30 guests or less, you can encourage your kid/s (preschool age & up) to help you do homemade invites. Special paper (P30-40/pk at NBS) + 2-3 sheets of stickers (P10/sheet sa palengke or mall tiangge, like in Shopwise Cubao), pentel pens/colored pencils plus their own artworks & handwritten notes, especially if they're fond of drawing. Or let them make the invites in Powerpoint /other software for emailing to relatives & friends.
3. Instead of typical games ("Bring me," "Longest happy birthday,"etc.) try setting up 2-3 "stations" where kids can just play (Bubble-making, craft-making, car racing, LEGO building, UNO, pet corner if you have relatively harmless pets like non-snapping turtles, small rabbits, etc.). Maximize whatever toys & games, which are still in good condition, that your kids already have at home.
4. If you want guests to mingle & have fun, try doing your own Human Bingo cards - 1/4 bond size, with a printed or hand-drawn table with 4 or 9 boxes. In each box write a descriptive phrasë, e.g., eldest child, only child, long hair, likes to draw, works in a bank, has 2 kids, newlywed, likes anime, plays online games. Give each guest a card and give the group 1-3 minutes to complete their cards by going around and asking people to sign their name in the appropriate boxes; first with filled out card wins.
I hope these help...