Mods: note to move thread to Thailand forum where it will get more airplay.

That's a really busy time for travel in Thailand so I wouldn't hold out a lot of hope that a great promo will come along applicable for that period. You can check on www.bangkokair.com for website direct pricing if you haven't already, but $300 pp round trip sounds about right. Except for a daily flight or two on Thai that's similarly priced, PG has a monopoly on USM. I don't think there are other options to get there by air.

If you are willing to consider flying to Surat Thani airport (Thai Airways TG or Thai Air Asia FD), then having a driver and minivan meet you and go by road/ferry over to Samui, that might be more like $200 pp (TG) or $100 (FD) round-trip air then maybe another $100 total to get you to the Don Sak ferry pier where you can buy tickets over. I think there is also a bus/shuttle that has a bus/ferry combined ticket for about 600 Baht-ish. From airport to pier is about an hour-ish if you go direct (not into Surat City) and then ferry crossing will take about 1.5 hours. Add whatever waiting time at pier to make connection. You'd have to look at flight arrivals and ferry departure times to see if it works for you, but it is a lot cheaper than USM direct flight esp if you can get an Air Asia flight. FD sells out quickly so you have to buy well in advance (like...soon). And it's a low cost carrier, with lower baggage limits, stiff excess fees, no frills, and no refunds.