Those are now worthless due to the age and crash issues. The P4 you listed is only slightly better. The OS is the only item of value there but take that away and you may find that for free on curbs and Freecycle.
Take the P4. Give no money.
Bob
Hello need some advice. Which would be the better machine the Dell optiplex gx270 or emachine T2080.
Emachine T2080
CPU : AMD Athlon? XP Processor 2000+ (1.67GHz) with QuantiSpeed? architecture
Operating System : Genuine Microsoft

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic