If you're looking for part bag fillers at a fair price, do check out this pack of 12 glider planes, currently on offer at Amazon for just £1.69 and reduced from £6.99.
I'm always amazed by what a big hit these glider planes are with kids. My lads have been given them many times, either as little extras in birthday / Christmas gifts or in party bags, and they're the sort of item that they cherish and end up playing with quite literally for hours.
This particular item has been rated 3.4 out of a possible 5 stars by people who have purchased them, but I'm guessing that's because some folks perhaps didn't realise what they were buying and expected something of a higher quality than a little styrofoam plane.
Here's one of the more positive reviews to give you an idea of what people think:
"Brilliant just perfect for son's birthday party loot bags - a bargain price, well worth the money. Definitely a good buy."
These particular ones are sold and dispatched from Premier Life Store, so not fulfilled by Amazon themselves, but you also get free delivery which is pretty spectacular. Maybe the planes fly directly to you?
With thanks to clare1987is @HUKD