So I have three kids - which makes life tricky when arranging the family holiday. Most 'deals' tend to assume a family is a maximum of two adults and two kids - which means when we travel we almost have to double some of the accommodation costs - two hotel rooms, etc.... and not only does this mean it cost more, but also you have issues with ensuring the rooms are next to each other.... my wife and I have to split up as we can't have the kids sleeping in a separate hotel room by themselves.... it just doesn't make for an enjoyable holiday.
Anyhow, I though this might be an opportunity to list some of the sites I'd found as well as ask if anyone had their favourite travel sites and tips on getting the best travel bargains. Not necessarily only dealing with larger families, but at least making mention of it if you know of anything!
So I'll start the ball rolling:
* Some of the voucher/group buy deals can be good value, although you do need to be wary of expiration dates combined with the possibility that (if it's popular) you may not be able to get the dates you want. Definitely do NOT leave booking to the last moment
* If going overseas, as crazy as it might sound sometimes (in particular now that the $AUD is so strong) it can be cheaper to buy the tickets overseas - eg going to http://www.expedia.ie/ rather than http://www.expedia.com.au
* In general, I'd try to book the flights first and *then* arrange the accomodation. That way you get the best deal on the flights, and you will always find somewhere to stay
* Check sites like http://www.seatguru.com/ and http://seatexpert.com/ to pick the best seats [best leg room, away from the toilet queue, etc]
* Currency conversion - http://coinmill.com/
* Rather than enable global roaming on your mobile, consider picking up a prepaid sim overseas - you can get really cheap deals that include mobile data.... frequently [for a small premium] you can arrange for the number before you leave, so you can let people know what it is before going
* Hotels frequently have special arrangements with businesses to provide discounted room rates, including broadband access and even breakfast. If you work for a larger company, it may be worth asking when travelling - as even when not travelling on business most hotels will still allow you to book using the agreed company rate
* Hotels also don't like empty rooms - so provide special deals at different times to keep the occupancy rates up - there are a number of sites out there that advertise these rates (eg lastminute and needitnow)
Some sites:
http://www.byokids.com.au/
http://www.travelzoo.com/au/
http://www.expedia.com.au/
http://www.lastminute.com.au/
http://needitnow.com.au/
http://www.ratestogo.com/