Prices obviously vary even for limos. But the limo companies are not fools. They set prices according to what they believe the market will stand. I don't visit Pattaya often and usually it is to stay with friends who live about 15 kms north east outside the city. Last time I took a limo service that was cheaper than that offered by Olay. Despite my having used the service more than once before, despite the young driver having received the location from his boss and my giving him the GPS co-ordinates AND the address in Thai, he had it in his mind that I was going to a hotel near the Dust Resort - and none of my protestations would persuade him that I was going nowhere near there. Attempts to reach his boss were unanswered. Once at the hotel, the driver finally spoke to someone on the phone, but nothing was resolved. Thankfully my friends were not doing anything at that time, So they were inconvenienced by having to drive all the way in to that location to find me and pick me up.
If you are going to a hotel I doubt if you will have this experience. In that particular case I would happily have paid the higher fee, saved a lot of time and avoided intense frustration by using Olay.