If you wanna try going the build your own route:
Minimum System Requirements
Operating System: Windows® 7 / 8.1
CPU: Intel® Pentium®III 800Mhz or faster processor
Memory: 128 MB RAM
Graphics Card: NVIDIA® GeForce™ series with 32 MB or ATI® RADEON™ 9000 series
Sound Card: DirectX®8.1 compatible sound card
Hard Drive Space: 9.5 GB free hard disk space
Other: Keyboard, mouse, DirectX8.1 (included with install disc),
CD-ROM drive (used only when installing)
*For PlayOnline/FINAL FANTASY XI: Ultimate Collection, Vana'diel Collection(s), Aht Urhgan, and Wings of the Goddess, a DVD-ROM drive is necessary for installation.
Recommended
Operating System: Windows® 7
CPU: Intel® Pentium®4 processor
Memory: 256 MB
Graphics Card: NVIDIA® GeForce FX™ series or GeForce 6 series
Sound Card: DirectX®8.1 compatible sound card
Hard Drive Space: 9.5 GB free hard disk space
Other: Keyboard, mouse, DirectX8.1 (included with install disc),
CD-ROM drive (used only when installing)
*For PlayOnline/FINAL FANTASY XI: Ultimate Collection, Vana'diel Collection(s), Aht Urhgan, and Wings of the Goddess, a DVD-ROM drive is necessary for installation.
newegg is a pretty great place for building computers. If you're uncomfortable trying to build your own, you could troll craigslist for a while and try to snipe a deal. I got a setup worth roughly 3k usd for 800 from a guy a few years back who was moving and couldn't take it with him.