Hi. Uhm ... I don't really deal with hand-held consoles anymore, since they're a pain in the butt due to small/cheap parts used.
Let me know what version PSP you have, PSP-1000 or PSP-2000 so that I can find out the correct part you need.
Planet Gaming in JHB is the best when it comes to PSP and Nintendo DS stuff. I usually send client PSPs to them with the relevant part needing replacement. Then I charge the client for the part and shipping to and fro.
The on/off switch with surrounding PCB that plugs into the motherboard will cost in the region of R140. Will take 2 weeks or so to arrive from overseas.
The warranty will be covered by me (3 months).
If you're happy with the terms and conditions, I can help you out.
p.s. Don't have a 'friend' mess around with electronics unless they know what they doing. I get way too many consoles where I friend helped out and broke stuff even further ...