By no means a tight wad but I like to go for anything cheap, generally speaking..
Bread in all it's forms has given me the best fish by a country mile. From floating to a pinch of flake it's just a lovely bait to use. NOT a easy bait to use CORRECTLY, nor a bait where any sort of loaf will do, but get the various factors right and it's top notch. Great for chub when floated and very exciting fishing !
Elderberries, well I love them BUT they are possibly the most difficult bait to entice fish. Like Tares, they do take a while, and I'm talking weeks here, to become even remotely successful and many give up far too soon. On new waters I fish them on a separate rod (the only time I use two rods) and just keep trying. Being very seasonal and short at that, most will see them as a waste of time.....
Slugs; My wife would love me to take the hoards that invade the garden, but never done anything
Boilies; I use them from time to time, but I just think I'm fishing a bait made up by others and they take little skill IMHO, just choose a flavour - how boring ! Saying that, pineapple flavour has done pretty good occasionally...
ps He above who uses Marmite; Only my opinion but it's vegetable based, if you can call it that, and not great IMHO (who has used it countless times comparing the two) so I prefer Bovril which is beef extract, again, if you can call it that, which has given me many bonus fish when meat starts to lose it's appeal in a session. It is a pain and messy to apply so I'm using a small brush at the mo to 'paint' it on after a fashion BUT well worth while on my waters at least and definitely at this time of year !! Also good smeared on floating baits as well...
Best of all - it's as cheap as chips !!!
ps Sorry for the long post - three lines would have done but I don't do them !!!