A Thai amulet (or talisman) is  usually depicted in the image of the Buddha or a famous monk and is worn (or carried) by Thais for luck, protection, and inspiration. Amulets come in different types of medium including (but not limited to) brass, bronze, silver, gold, clay, terracotta, semi precious stone (naga), chrystal (naga) BUT NOT GLASS nor LEAD CHRYSTAL etc. some are mixed with cremated remains, chips of precious stone etc. There are many of these to be found on ebay and often at a reasonable price. Many sellers claim that their amulets have "special powers" and to "beware of fakes". Well I won't even comment on the "special power" claim and yes some amulets can be faked but Thai amulets are very common and inexpensive to begin with leaving little room for fakes. For example in Thailand (where I live) to obtain a authentic amulet is as simple as walking into a temple and giving a donation (or as Thais refer to, making merit) for as little as 100-150 baht ($3-5 dollars) and you can have your very own amulet. Although Thai amulets are very common and inexpensive  there are some very rare and expensive amulets. Like babeball cards, rare coins or paper money, or any collectable for that matter, amulet prices can fluctuate depending on production runs, (fewer that are produced, higher the price), popularity, and how fast a particular amulet sells out, medium used, etc...  Unless you have knowledge of various amulets you are best to stick to the more inexpensive ones . Be wary of sellers who are selling "rare" amulets  because there is a good chance that if it is advertised as being "rare", it may be more common than you think. I don't mean to contradict myself but some very popular amulets that had a limited production run or sold out fast have been "faked" like some Jatukam amulets so when in doubt ask questions (i.e. does it come with its original plastic case? What temple produced it? etc.). So remember as a rule of thumb, a common authentic Thai amulet (and there are many beautiful ones) should cost you under $20.00 U.S. (excluding solid gold or solid  gold casings) including shipping! I have even seen authentic amulets on ebay going for as little as $5.00. They may not be worth much from a collectors standpoint but authentic all the same. ( authentic Jatukam amulets-$25.00-40.00) A real chrystal or semi precious stone naga (eye of the Buddha) can run you anywhere between $25.00-$50.00 (depending on medium used) including shipping but BEWARE of glass and lead chrystal fakes as there have been many spotted on ebay. Also beware of brass or bronze Buddha "coin" amulets. Although there are many authentic brass/bronze amulets (I have many in my collection obtained at the temple that produced them) there are  many fakes that come out of China and sold in markets all around Thailand occasionally making their way onto ebay. Any questions or comments, please feel free to contact me.