Surprisingly, there is still plenty of land around Pattaya available. In fact outside the city suburbs there is nothing but empty land. In the Pattaya area land has continued to appreciate, but the high value land is just sitting and waiting for a rich opportunist. For example, near the beach in Jomtien land goes for about 6 million baht a rai. If you drive around Jomtien there seems to be a lot of undeveloped land available.
Before you read any further, be aware of the Thai land laws that prevent foreign ownership. The most common means of getting around this is for a foreigner to place ownership in the name of a Thai spouse, or even friend, but you run the risk of losing it to an untrustworthy person or estranged spouse. Since the government started more vigilantly checking on the status of companies set up by foreigners (apparently with 51 per cent Thai ownership) in order to own land, this method has become risky.
To find land on which to build you will need to get out of town a bit, but not far, about 10 minutes by car will do. Then you can build a nice sized residential house. Selection of area is very important as there is so much surrounding land and demand for areas is spotty. There is no proper zoning in Thailand and no such thing as rich and poor areas, generally everyone is mixed in. Real estate agents can sell you land, but they are of little help in taking you around and showing all of the different areas. That is because there is no multiple service for listing in Pattaya for property on sale.
There are many types of land ownership in Thailand, but you should only consider deeded property. The deed in Thai is called chanote. A lawyer can help with the land transfer for a fee of around 5,000 baht, but make sure he does the due diligence properly. There is no problem here with questionable land papers as there was in other provinces since Pattaya is a relatively new city with no vague historical land claims. You can do the property transfer at the land office yourself, but the lawyer option is worth the money considering all contracts and documentation must be in Thai language.