The fee depends on what type of Thailand Visa you are going to apply for. Thailand Business Visa, student visa, marriage visa and retirement visa in Thailand can all be valid for 1 year.
Non B or business visa is very common for foreigners who would want to stay in Thailand for 1 year just to travel around. Normally you would be required to have a Thai employer to be able to apply for this visa but there are companies providing services to assist you with the process.
Visa fee in the US 175 USD
Visa fee in the UK 100 Pounds
It is going to depend on what type of visa you want - the fee for a retirement visa is 1900 baht - if you want multiple entry add another 4000 baht - but to get a retirement visa there are requirements, both age and income - 50 and either an income statement or a deposit of 800,000 in the bank.
A retirement visa in Thailand will cost you 1,900 baht, and 3,900 baht for a multi-entry visa. A multi entry visa lets you leave Thailand and return during the one year period without losing your original visa.