Flights to Kuala Lumpur/Phuket - websites for discounts?

Hi,

We are hoping to go to Thailand next April. We have a Malaysian friend, so we are thinking IAD to Kuala Lumpur for a few days, then on to Phuket from there.

The problem is that my husband cannot sleep on planes if he can't lay down. We travel a lot and he has tried everything. This is bad enough when we go to Europe or S.A., but with 24 hours to travel, it would be a nightmare.

So I am thinking that we'll get one business class ticket (with seats that go fully flat) and 1 coach ticket, but of course the business class tickets are very expensive.

Any inside tips on where I should look to get the best deal?

Thanks,
K