NYX Professional Makeup is an affordable brand of cosmetics. It's not quite the cheapest but its widely available, and everything I've tried - mostly their lipstick - has been good quality. It's a solid choice for everyday wear, without costing a fortune.
I've tried several of NYX's darker-coloured lipsticks, listed below. The colour descriptions are based on my observations, not how the company describe them.
I have a preference for solid 'bullet' lipsticks over liquid lipsticks, mainly because I'm better at applying them neatly. I need to use a pencil liner for liquid lipsticks, but I can cheap out and skip them with the bullets. With dark colours like these, wonky lips are really obvious. I also find that the bullet lipsticks have better coverage then liquid ones, although that may not be true in other brands. The swatches image on this page possibly doesn't do the liquid lipsticks justice as no liners were used, and I didn't layer the colours as much as I would normally. It should give a fair idea of their colours, however.
I tend to alternate between Goal Digger and Doom, partly depending on my outfit: I'll choose Goal Digger if I'm wearing my usual black with red accents, Doom if I'm accessorising with purple.
Overall, I like NYX's lipsticks. They wear well without being too drying, and they have some really dramatic dark colours in their collection. At full price, they range from £6 to £8 per lipstick, liners to go with the suede colours are £4 each. They are available at Boots, Debenhams and other high street shops, or direct from the NYX website. At the time of writing, the NYX brand is cruelty-free, although their parent company - L'Oreal - is not.