Okay - so red or blue.
If you do Lifeguard - then a good solid red will do such as Humbrol 19 Bright Red Gloss - for the coat. If you want to tone it down a bit - put a "touch" of black alongside it and touch it in. I use it plain - love a bright splash of red. I use Flesh 61 Matte as a thin undercoat for red - makes it cover better and gives a nicer top-coat. You will also need flesh for the face anyway. Incidentaly, Brown 62 Leather Matte is good for shading with Flesh - and is good for leather reins etc. For the white - I actually prefer to use Ivory 41 (Trousers, gauntlets, eyes etc). Covers better - and isn't quite so harsh as pure white. Wite & Black make grey - so don't need to buy that.
Silver 11 and Gold 16 - are good to have for helmet/badge and breastplate. Black is good - I prefer to use Matte 33 mainly - though Gloss 85 is good for the boots. Paint the spurs first (silver) then go around them carefully with black - looks lovely if your careful. If you want a more "gunmetal look" for weapons/armour etc - a tiny touch of matte black with silver makes it darken a bit - specially good for gun-barrels I think.
Blues & R's - I use Matte 104 Oxford Blue - again with a touch of black to darken slightly for the coat.
So that would be sufficient basic colours to give you enough to do either HC type - if you use Humbrol - which the shop is probably more likely to have. Maybe buy a yellow too - if you are going to do bases in green - remeber yellow and blue make a green - though a tinlet of Green 102 Army Green - is always a good standby to have around - yellow will lighten that too.
Incidentally - I never dip brushes directly into the tin. Use a cocktail stick to put a drop or two of paint onto a marge tub lid (palette)Then a drop of the other paint near it - then use the brush to blend to the shade you want. ALWAYS put the lid straight back on the tin - it will last longer that way - or you risk it going hard - and throwing a half full tin of solid paint away. You can buy thinners - to thin thickening paint down - but I just use white spirit - as you need to clean your brushes every time - I use this with tissues to clean them thoroughly.
Good luck with them - and have fun - johnnybach^&grin
I have done both HC types using these colours - so that ought to get you going.