Most property purchasers will be asked early on in a potential transaction to provide evidence of their sincerity by placing a deposit. Deposits can vary between a few thousand Thai baht up to a significant percentage of the purchase price. Sellers don't want to waste their time with buyers who are not bona fide. Buyers don't want to lose their money whilst investigating whether or not a sale suits them or is set up appropriately. This tension can be dealt with but often only when a buyer is prepared to take the risk of losing out on securing the property to protect the deposit sum by not placing any monies until comfortable with the proposed transaction.
Many local private sellers will not accept 'escrow' arrangements. In these circumstances it is recommended that all due diligence is conducted as quickly as possible (the only buyer who will pip you to the post is a buyer with less caution and they may be rewarded appropriately) and the sale is conducted as a one-off payment and registration on one day. Even if a buyer offers to give you the land documents as security, remember that until you have all the documents necessary to effect the transfer at the land office without being challenged, the original land document is not worth anything or much to you. In complex land transactions involving registered rights of redemption or unregistered contracts where numerous land agents are involved, no deposit should be paid until it is clear that the title will be eventually transferred to the buyer and at no stage will you be required to pay a third party to whom the seller owes monies/obligations without security.
Finally, caution should also be exercised when placing deposits in relation to development projects. Terms on the reservation sheet will normally not refer to refunds in the event that title isn't clear or terms are not agreed. They will also require signing and payment more swiftly than a typical due diligence and contract negotiation process should take. A buyer will be assured by experienced development project sales staff that the title for the land on which the project is built must be clear because the developer will have spent a lot of money investing in the land and will have checked this already. Ask to see a definitive guaranteed title report and legal opinion which you can rely on and this will more often than not - be unavailable. If it is available it should be verified by your legal representatives. If you seek a refund in the event that terms are not agreed you may be greeted with the response that all contracts have been carefully crafted and although you are free to have them reviewed by a lawyer amendments will not be accepted. When the contracts are actually reviewed and large risks for you uncovered it may be a more costly exercise to walk away if a) contracts are unreasonable or b) contracts are only partially prepared and you are expected to make initial payments without the complete set of documents relating to your transaction being agreed.