A taxi ride would be at least 3000 Baht, but from the Airport you have taxi stands with fixed prices for most destination.
From downtown Bangkok, you can negotiate to as low as 2000
Baht.
The less expensive would be to take the public minibuses.
Thais use them for transport between provinces.
Most of the minibuses can be catched at Victory Monument.
To go there from the Airport either take a taxi (about 200 baht), or take the Airport Link to Phaya Thai.
There are one rapid (100 baht I think) and one that stops to every station.
At Phaya Thai, take the BTS to Victory Monument (one stop).
Vans depart from several places under the Skytrain station (near Century mall), normally from ~7am to ~8pm.
So total for the less expensive trip would be Airport Link (45 baht) -
>
Bts (15 baht) -
>
Minibus (~200 baht) =
260 baht.
More infos :
Bangkok public transport map , Getting to Hua Hin
travel.stackexchange.com/users/92/Thomas Joulin
Try this: http://airporthuahinbus.com
It is 305
Baht for a trip from Suvarnabhumi to Hua Hin on a bus with AC.
Estimated travel time is 3 hours .
This service is brand new, it just started on 29 November 2012.
travel.stackexchange.com/users/3658/wotchit
The best way is to stay at the Inter-Continental and charter their Cessna for the 35-minute hop .
But at 50,000 baht one-way, this may not be all that cost-effective ;)
travel.stackexchange.com/users/1893/lambshaanxy
Use Train, take "Airport Rail Link (SA City Line)" : Airport >
Makkasan station (45THB) 5 minutes walk : Makkasan Station > Phetchaburi Station (MRT-Metro) take "MRT" : Phetchaburi Station > Hua Lamphong the Thailand Train central (29THB) take "Train" :
> Hua Hin , there are more than 10 times a day (44THB-202THB depend on the class) Budget 45+29+44= 118THB Time overall around 5 hours PS.
check the train time table at http://www.railway.co.th
travel.stackexchange.com/users/2812/Fawas
Bell Travel bus desk on Level 2 of the Airport has shuttles that run regularly, best if you book on line as they sell out, Around THB260/per person.
Air conditioning, toilet, wifi, reclining seats.
Around 3.5 hour trip but definetley the cheapest and easiest way to get there.
Not associated with this company just a happy customer.
travel.stackexchange.com/users/35765/Mr G
I think a metered taxi from the airport (Suvarnabhumi) to Hua-hin should be around 2,500 Baht
, I did a quick online search and found a company called oriental escape that offer airport or downton pickup and transfer to Hua-hin for 2,650 Baht in an economy car (toyota Soluna)
so a taxi should be a little bit cheaper than that, I usually get a taxi from Sukhumvit to Hua-hin and pay around 2,200 Baht!
travel.stackexchange.com/users/883/Phillip Evans
there is actually no question of what is the best way.
The best way is CLEARLY by Bell Travel bus ( http://airporthuahinbus.com ) easy online booking new 24 seater bus 3
super wide fully reclining seats in a row
smooth ride 3.5 hours travel time price 270 baht
The second best way can be hiring a private car online
Camry/Innova car not as smooth as a bus, surely will make you more tired roughly the same travel time price from 1800 baht Trains may be fine, but it will take much more time old smelly train first take airport link train then change to MRT then walk to the railway station and buy tickets trains are super slow and NOT NICE Don't ever think about taking a van from Bangkok, it's a horrible experience, not foreigners should travel this way...
It's inhumane.
travel.stackexchange.com/users/39481/Eugene Oleinik
I have used www.bangkokshuttle.com several times to get from the airport into downtown Bangkok.
Apparently, they also serve Hua Hin for 2,800 THB.
Clean and hassle-free.
Disclaimer: I have no affiliation with Bangkok Shuttle other than as a satisfied customer.
travel.stackexchange.com/users/872/arboc7
I have travelled many times to Hua Hin.
The most cost effective way to travel is by train as Fawas described above, another easy way is using the airport bus shuttle, but.. I have had to wait almost 2 hours sometimes before leaving the airport, and that is not really great after a 11 hour flight and then another 3 -3½ hours in the bus.
But the buses are comfortable.
What I normally do is book a transfer by taxi from a Hua Hin based taxi company, there are several you can find on the net, but lately I have used www.huahintaxiservice.com simply because the reply fast and have good communication skills in English when I book the trip.
As mentioned I have tried others and all seem to have good cars and good drivers, price for one is between 2200 to 2500 THB.
travel.stackexchange.com/users/6316/Anders
If your goal is get the cheapest journey do the following Airport rail link city line to Lot Krabang (next station) (15 Baht)Take the train to Bangkok (6 Baht)Hualamphong to Hua Hin
travel.stackexchange.com/users/6533/Sebastien
This is what i would advice and also an extra tip... Save yourself the stress , worries and the dragging with suitcases and spend the few baht/dollar/euro and take the Bell bus which cost 305 euro.
It is quite fast and very comfortable.
If you are at Hua Hin, you probably can walk or take and if not, take taxi from the busstation to your resort/hotel.
2200/2800 baht for a taxi is really overpriced.
If i have to wait an hour extra, then i will have lunch or dinner there.
A 3-4 hour drive to Hua Hin with an empty stomach can be a longggg ride.
What i would recommend is leave a day earlier Hua Hin, and take an airport hotel for 1.5 or 2 nights.
They offer often free shuttle from/to the airport.
Because my flights from BKK to my destination departs at 2AM i will book an extra night, so i will leave the hotel at 22:45pm and be 3 hours before departure time at the airport.
At daytime i can relax and swim and get a last glimp of Bangkok if i want, and then take a rest, and then shower and head to the airport worry and hassle free.
travel.stackexchange.com/users/19926/Chris
What is the most cost effective way to get from the Suvarnabhumi Airport to Hua Hin (on Thailand's northwestern Gulf coast)? And how much would that be compared to a taxi ride?
Which transportation is best from Bangkok Suvarnabhumi Airport to Hua Hin?
travel.stackexchange.com
<budget><airport-transfer><thailand><taxis><bkk>
travel.stackexchange.com/questions/1874
travel.stackexchange.com/users/722/Lawrence Leung
A fixed-price or metered taxi ride would cost around 3,000 2,500 Baht, which can be booked online or at the airport. You can also hire a private car from about 1,800 Baht. There are also public minibuses or shuttles that can be booked for about 260 THB, but these often require a long wait. Trains are the most affordable, but can be uncomfortable, slow and smelly and may need several changes. There are many ways of travelling from Bangkok airport to Hua Hin. The cheapest ways seem to be the train and the minibus. A more comfortable, faster option that can be booked online is the Bell bus. Taxis are available at a cost of 2500 to 3000 baht, some companies offer online booking. Private cars can also be rented online but are tyring as you have to drive yourself. Finally, the Inter-Continental hotel has a Cessna you can charter. 
Taxis from Bangkok airport to Hua Hin cost around 2500 to 3000 baht and take 3 - 3.5 hours. They can also be booked online. Minibuses are not expensive. The Bell bus is a good service, not too expensive and can be booked online or at the airport. Private cars can be booked online but the journey takes the same time as the bus and you have to drive yourself. The cheapest method of travelling from Bangkok airport to Hua Hin is the train. The Inter_continental hotel has a Cessna you can charter, journey time 35 mins.