I would recommend the Collection felt-tip eyeliner. It lasts all day and doesn't smudge easily even though it the pigmentation is strong. And it's only £2.99! I know felt-tip liners aren't for everyone but I find them much easier to apply than gel.
It also depends on how thick you like your liner, because the Collection one is not the easiest to have really thin lines (but I like it a bit thicker). If you do want a simple, small line, the L'Oreal felt-tip is thinner to apply with. I use it to sharpen up the points of my flicks
Without a doubt Stila Stay All Day waterproof liner. They have a variety of colours available and they last for hours. I put mine on at 7 AM this morning I haven't reapplied it at all and this is what it looks like now 13 hours later
I buy mine from boots and its around £13 but it lasts 6 months with everyday use.
The Soap & Glory Supercat eyeliner is by far the best liquid eyeliner I've ever used. It's so easy to use and lasts for ages compared to other ones which dry out so easily.
dumb question but are you supposed to apply it to the bottom eyelid as well?
I know people who only apply it on the bottom, personally I just apply it to the top most days, with sometimes a little on my waterline. I only put it on halfway across the bottom and 3/4 of the way across on the top so it's not too heavy looking. Basically just try stuff and see what looks right with your face, generally less is more for an everyday look.
This one is just my favourite thing I've ever put on my face, and the only make up I ever take with me if I'm camping, sleeping over etc.
I use it every day and it still manages to last me a good 3/4 of a year. I only bought it at first because it's the cheapest one you can get where I live.
dumb question but are you supposed to apply it to the bottom eyelid as well?
only if you want to but would not recommend liquid/gel ones for the bottom of the eyes because it will sting if they touch your waterline. Only use pencil or eye shadow at bottom of eye and pencil only for both waterlines if you want to apply eyeliner there