New graphics cards cost peanuts, I needed a new graphics card for my server PC, the cheapest thing I could find (almost*) was a GeForce 6200 so I snapped it up and plonked it in. That is all you need to run LFS at high res with AA + AF, so long as your CPU is up to it.
*There were some ancient POS cards available but the difference in price was only a couple of pounds, they weren't worth considering.