Looking for *extremely* low graphics FPS games.

Fortix. All the way baby.

System Shock 2? You should be able to catch it on sale pretty cheap..

old Medal of honor

how abt this? Not the best there is but you can get good laughs while playing it. I know I do: 1 2 3

While I know this won't help, single-player and F2P? Those rarely exist, especially in the FPS genre. And there won't be anything that cheap without being on sale.

What comes to mind is: Medal of Honor: Allied Assualt, Quake II/IV, Doom 1-3 (I know, no real story in the first two) and maybe even Aquanox 1 & 2 (It can be first-person and ships strafe so it's close). Oh, and SiN Gold came out on GOG a little bit ago.

Halo? I know it isn't a steam game, but it's still great.

Unreal. I used to play it and Half-Life on 320 * 200.

Oh, and the Doom games. FreeDoom would be something you could look at.

And Chex Quest is free as well.

Please note that my graphics is especially bad at rendering particles. My framerate even drops down to less than 10 on Half Life when I'm looking at smoke/fire.
There has to be something wrong with your settings. I played that game on a P166 with 16MB of memory and a 1MB video card. I won't deny I had the graphics turned down, but your PC should have no problems with Half-Life.

have you checked Loadout ?

Not singleplayer, or on Steam, but check out Urban Terror.
Maybe Chrome and Chrome SpecForce?

Return to Castle Wolfenstein

Star Trek: Elite Force

Great story, great game, great fun.

Republic Commando or any Jedi Knight game ranging from Dark Forces all the way to Jedi Knight 2: Jedi Outcast(can be considered FPS). However Jedi Academy is a Third Person Action game

Delta Force Games

Vietcong, Delta Force: Black Hawk Down

Doom 2, play it with Zandronum to add tons of graphics and customization options.

None of the FPS games you mention are "extremely low graphics." Something like Quake or DOOM would be low-end graphics (or Castle Wolfenstein, if you really want low-end). Anything made prior to 2005 should be OK for your rig. Plenty of older games were actually more entertaining than today's "modern" shooters. Check out Duke Nukem 3-D or Shadow Warrior Redux for an example of old skool shooters. GOG.com has a bunch of great FPS's for cheap. If you're looking for something more familiar, however, you might try some of these:

• F.E.A.R.
• Call of Duty 1 & 2
• Unreal Tournament 2004
• DOOM (the original)
• Quake (no story, but still a lot of fun)
• Serious Sam 1 * 2
• DOOM II (Final DOOM)
• Quake 3
• Medal of Honor: Allied Assault
• No One Lives Forever
• Return to Castle Wolfenstein
• Star Trek: Elite Force
• Red Faction
• Max Payne 1 & 2
• Star Wars Republic Commando (or any of the SW shooters)

I recomend you to wait for retro blazer. New, low graphics with awesome gameplay. In the current state its alfa, but just look on the screens. Cheers!

-shadow warrior classic redux (10 €) or shadow warrior 1997 version (free2play on steam)

-duke nukem 3d: megaton ediotion (10 €)

or both for 13,99 €

-far cry 1+2

-doom 1+2

-quake 1+2+3

-hexen 1+2

Thanks everyone for the suggestions!

well I have kinda the same PC as yours.. only with a more terrible spec.
I can recommend : Area 51 ( 2005 ) http://www.fileplanet.com/216672/210000/fileinfo/Area-51-%28Free-Game%29

I played it at lowest setting... graphics is nice ( well for me , been playing a lot of games with terrible graphics.. so far this one looks good )
It's not a steam game. It was a pay to play game , but now it's free and yes .. it's legally free. You can find other sources too for the download :p

Why don't you try the original Deus Ex? I know it's a bit of an rpg but it was fun back in the day.
Edit: I forgot Soldier of Fortune, it was pretty interesting for its time.

Aliens versus Predator 2! It is one of my favorite FPS of all time and the story is really good (especially if you are a fan of the AVP universe). It should run fine on your computer. There are also 3 separate stories that weave together in clever ways. Each story has a completely different playstyle. If you haven't played it before, be sure to check it out.

I don't think there is such a thing as a low graphics free to play fps with good gameplay and story.