Does everyone forget the batteries?
I spend anywhere from $100-$145 forLithium-Poly batteries, the pcb, and the charger from
http://www.batteryspace.com" onclick="window.open(this.href);return false; for every major power hungry portable I build.
Theres no way to get them cheaper unless you use inferior batteries or heavy less effective batteries.
So the price is usually as follows: (averages)
Psone screen : $60
Batteries Lithium-Poly - $120
System : $35
Third party controller: $15
Tact switches / buttons /caps/ etc : $20
Case (either premade or frankenmod) - $20
Wires / solder/ resistors / regulators/ etc - $25
Sandpaper / Paint / plastic filler/ bondo - $40
Time : Priceless
Total : $315
Granted that is worse case scenario , ie : you have nothing laying around to use. But it still is the value of what it costs.
So you can take your" $300 is all it's worth" and go buy a PSP.