Question about HL2

Not really I would say.

Yeah. It continues from the cliffhanger that HL1 ended one.
You could play Black Mesa instead of getting HL1, but I'm not sure if that's completed yet.

IDK, I don't enjoy the series personally your money would be better spent on some other game

You will enjoy it, even without playing HL1. But you can actually play HL1, it is still awesome, even with old graphics. Or you can play Black Mesa mod, it is basically HL1 remake.

I actually played HL2 before I played HL1, and I would have to say: Not really. During the events of HL1 you aren't told what is really going on. All the important story bits actually happen between the two games, and the player is brought up to speed through exposition and little notes in the game world. I highly recommend playing Black Mesa though. It isn't finished yet, (the last zone is still missing) but it's still very much worth playing. Hopefully the BM team will do as good a job on the final levels as they did with the rest of the game.

Long story short, you're missing almost nothing.

You should play Black Mesa, but if you don't want to and just want to know the story reading the wikipedia would be enough.

Buy HL3 instead.

Read this http://members.shaw.ca/halflifestory/timeline.htm

Here's some stuff you find out in the first level of Half-Life 1 -- you're Gordon Freeman, an MIT research scientist and it's your first day on the job at your new place of work, Black Mesa. There's lots of scientists, and also some security guards. Your first task is to put a specimen of some kind into a test chamber. Then a lot of bad shit happens. But you find a crowbar.

The security guards in Half-Life 1 were nicknamed Barneys because of their resemblance to Barney Fife from the Andy Griffith show. Barney is the official name of a security guard main character in the HL1: Blue Shift add-on.
Many of the scientists in HL1 resemble the character Doctor Kleiner in HL2.
And one of the signature baddies in HL1 is the headcrab (they're all over the inside cover of the HL1 box).

That's most of what's relevant to Half-Life 2 without spoiling any of Half-Life 1. Everything else is pretty much new or mildly spoilery. Except some of the sound library... there's a ton of reuse there.

+1 to playing the community creation Black Mesa (I still haven't, since I'm waiting for it to be finished, but I've heard many good things).