Invariably like most things in life if you leave it to the last minute then throwing money at the problem is probably the only option. If however you have your theme organised in plenty of time you can keep an eye out for anything that works with the theme as you go and are more likely to spot a bargain, have a flash of inspiration or have someone offer to lend you something.
Have a good look around in the sales prior to your party for anything that could be used as decorations or party bag fillers, I’m well known for buying all my kids’ clothes in the sales at least a year in advance and apply the same logic to birthday presents and party bits too! If you spot a favourite store doing items in your theme then keep checking back on their website at sale time, often stores you wouldn’t consider for party bag items might have one great piece hugely reduced. I’ve recently found dinosaur print aprons, ballet print bags, wooden bracelet sets, washbags, umbrellas and lots of other items which would be great favours all at £1-5 and generally 70+% off from places like Cath Kidston, Tyrrell Katz, JoJo Maman Bebe and GLTC.
Double up, make your party props do double duty
If you can buy anything for an activity that then becomes the party favour then even better. For example if you’re having a superhero or princess party then one activity could be to decorate your own superhero mask or princess wand that the guests then take home or if you need equipment such as aprons or rolling pins for a baking party then send them home as party favours.
Raid the house for any relevant toys that could be used or anything in the colours of your decorations that might coordinate (maybe decorative boxes, ribbon, photo frames)
Corodinating or themed wrapping paper could be used as a table runner to brighten a plain paper tablecloth and if you are having a dinosaur, sport or animal themed party you could find off cuts of artificial turf to cut as placemats or a table runner.
Get your children to draw pictures on the pathway or drive with chalk to lead guests to the front door, cut out a template before to help them. For example they could draw crowns for a Princess party, paw prints for an animal themed party, a treasure map for a pirate party.
Good luck and remember to save a few pennies for a well earned cold drink at the end of the party!