Do you have any toy warehouses near you? When my DH was on PA we used to go to a toy warehouse and buy stuff there for Xmas Bazaar/summer fete etc. Usually spent about 35p-50p per item but because they were from a warehouse they looked worth far more than that.
buy multi packs of stationery stuff and split. You could also buy huge bag of lollys or chews and stick a few of those in with a fluffy/novelty pen, that sort of thing. I also save all cracker toys for next years lucky dip and in January look out for bargains for next xmas as the supermarkets sell stuff off soooo cheap. Then store in the bottom of your wardrobe. ps, get your chritmas cards then as well, bargain!
yellow moon do nice stuff in the pocket money section - they come in packs of 12 for 2.99 for example, scented notebooks and creepy crawly pens and the like. And you can build up commission to spend on other stuff for school aswell.
Just as a heads up ... yellow moon is a side-arm of Baker Ross .. to be honest they load the commission they give to the school into the prices they charge for their merchandise (not all items but across a rather large range of them)
McDonalds toys for a paid-for lucky dip sounds really off to me .. at least it would be deemed unsuitable on many levels at my children's school