Just bought a big tv and there's a port on the back for pc monitor input. However i can't get my pc near enough and keep it plugged in to all the needy holes.

Are long cables (4-5m) around and if so, pricey?

I've seen VGA cables 10m+, not checked prices though but I can't imagine them being excessive.

I'd avoid cheapo cables, VGA is an analog system so long cables will degrade the performance, cheap long cables will degrade performance a lot.

I'm feeding the telly from a cheap (2500 Baht) PC that plays my content from a network drive, works fine and doesn't interfere with work when the missus uses it

Should be no problem, I have used cables up to 45 meters, but for this length a booster was needed (one these things allowing you to hook up 4 or more monitors to 1 PC, as often used in PC shop displays.

No detectable quality loss!

Good quality 5m cable should not be a problem...

Cheers lads (and lasses?)