I'm heading to south east asia in july till september/october time (money permitting) and wondered what the cheapest way to travel would be. I'm not booking tickets, im hoping to catch a stand by from heathrow to Bangkok. But is that the cheapest option? i.e. would it be cheaper to fly to Cambodia, or would it be cheaper to fly to thailand and get a bus over to Cambodia? (I have to be in Cambodia in august but wanted to catch the full moon party in Thailand first..)
Would be great to hear from anyone who can help or anyone that's heading out at the same time! 
Pip.
What's the cheapest way to travel around South East Asia?
You're travelling off season so that will be cheaper. Check different days for lower prices. A stop or two on the way can also work out cheaper, spending a few hours at some airport.
Standby? I thought that went out a dozen years ago? Nowadays generally the later you leave it, the more you pay (with the airlines believing there are few seats left so you can pay a lot more if you want to fly).
Bangkok being a travel hub is generally the cheapest as most flights go there.
There are a few cheap airlines in the area. Try AirAsia, which has to be booked early to get the bargains.
Book accommodation soon to for the FMP, as the cheapies quickly fill up.
From memory i took a bus from Bkk to Siem Reap last August for 500 baht! The cheapest way from Bkk to koh phangan is bus/ferry