I use pellets from Ton Up Baits 01442 390034 They come in different sizes and are cheap to buy. They need to be soaked for awhile if you intend to hook them, They have a never ending shelf life so they don't get wasted and are very good.
For feed I use Swim Stim pellets, You can feed your swim all day (little and often) and still have half a bag left at the end of a session. Both cost a little over 2.00 each for nearly a Kilo and I find they work very well.
Micro pellet bought loose or the Richworth ones are pretty good as a bed.At this time of year I tend to use caster or small red worm over the top.I have never really wanted to flavour them as they carry their own scent.