Here's a budget AMD build.
Rosewill R222-P-BK Black Steel ATX Mid Tower Computer Case - Retail
Model #:R222-P-BK
Item #:N82E16811147095
$29.99 -$3.00 Instant $26.99
Acer X223Wbd Black 22" 5ms Widescreen LCD Monitor - Retail
Model #:ET.EX3WP.001
Item #:N82E16824009145
$199.99 -$50.00 Instant $149.99
LITE-ON 20X DVD±R DVD Burner Black SATA Model iHAS120-08 - Retail
Model #:iHAS120-08
Item #:N82E16827106264
$25.99 $25.99
GIGABYTE GA-MA790GP-DS4H AM2+/AM2 AMD 790GX HDMI ATX AMD Motherboard - Retail
Model #:GA-MA790GP-DS4H
Item #:N82E16813128352
$138.99 $138.99
Antec Basiq BP500UB 500W ATX12V Version 2.01 Active PFC Power Supply - OEM
Model #:BP500UB
Item #:N82E16817371019
$39.99 -$10.00 Instant $29.99
AMD Athlon 64 X2 5000+ Brisbane 2.6GHz Socket AM2 65W Dual-Core Processor Model ADO5000DOBOX - Retail
Model #:ADO5000DOBOX
Item #:N82E16819103211
$59.99 -$10.00 Instant $49.99
A-DATA 2GB (2 x 1GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory Model ADQVE1A16K - Retail
Model #:ADQVE1A16K
Item #:N82E16820211066
$27.99 $27.99
Seagate Barracuda 7200.10 ST3250410AS 250GB 7200 RPM SATA 3.0Gb/s Hard Drive - OEM
Model #:ST3250410AS
Item #:N82E16822148262
$54.99 $54.99
Subtotal: $504.92