We did sweets/chocolates. So Skittles, Rolos, Smarties, Fudge Bars, Double Deckers, Mars, Milky Way, Wispa, Buttons etc.
We scattered fun size bars or mini packets on the table matching the name. It was quite fun as the guests used our nephews to negotiate swaps between the table "tell them we'll give them 3 packets of Rolos for the bottle of red wine that they're not drinking." It was one way of making sure that bottles of wine we paid for was being fully drunk even if at a different table and the more sober guests at least had some consolation chocolate.
The Smarties table thought they were the cleverest (mostly teachers and lecturers) but they soon found out that the Rolos table were the group most likely to be driving a Rolls Royce. Milky Ways were fond of travelling. Skittles were having the most fun. White buttons at one table with children. Ferrero Rocher at the top table because the ambassador was truly spoiling us.
This was as far as we went in terms of table favours, very cheap, all used. Possibly the cheapest way to do this nowadays would be by getting a couple of boxes of Celebrations or Heroes and sorting them into individual varieties. Or, near Halloween, you'll pick up the variety packs easily.