Many places come with their own furniture, though this varies considerably. Cheap cane furniture can be bought here to supplement what they have given you. Cheaper places may have really uncomfortable beds. The Thais are used to sitting on the floor or sleeping on rock-hard coconut husk mattresses.
 
When signing a contract make sure that you have verified (independently) that the English version you are reading is consistent with the Thai version, for it is the latter which will be used in settling a dispute. In any case, Thais prefer to settle things out of court (courts aren't always impartial), so make sure you have the upper hand.

All nearly all rental properties the tenant will be required to pay additional charges for electricity, water and telephone that are not included as part of your main rent. Also, due to the tax structure, all property in Thailand is rented as "furnished" - even where you may not want to make use of the furniture. Remember to check the cost of water and electricity costs. Many landlords will charge a fairly cheap rent but make thousands back a month on high utility bills.

The usual deposit for a condo or apartment in Bangkok is about two months of rent, while the rent for the first month must be paid in advance as well.

BUYING

Generally speaking it is better to rent than buy unless you plan to stay permanently (or most of the time) in Thailand, and be particularly wary if your goal is to make a capital gain.

If you do buy a condominium, you will in general have to prove that you have brought in the money involved from abroad. Banks have special forms to fill out for this purpose. So when you bring in the money to a Thai bank, with the purpose of using it to buy property, be sure to make it clear to your bank.

When buying, it’s generally better not to buy off the plan, as many people discovered in the wake of the 1997 crash.

If you own a property, you will be liable to pay a property tax. The amount of this tax depends on the estimated value of the property. You should check how much you will have to pay, though the rate may go up in the future. Expect between Bt10,000-20,000 a year for a two-bedroom unit. Other taxes will have to be paid when the property is bought or sold. Because of the peculiar local system of taxing property on a rather arbitrary assessed value rather than true market value, these could amount to as much as 30 percent of the purchase price. When a tax bill arrives ­ often some two or three months after the sale is completed ­ this could come as a nasty shock to a buyer, since the seller often neglects to mention this liability during the negotiations. Further, if the house is purchased through a company, one has to bear in mind that corporate tax is higher than personal tax, and the cost of setting up the company has to be considered as part of the initial investment outlay, even if this is a relatively modest additional cost.
Use the services of a law office, before you make a property purchase.

Maintenance fees are usually charged by the month, and the amount is decided in the yearly meeting of the owners (where you do have voting rights). A fee higher than Bt35 per meter per month, is possibly high, but all depends of course on the value of the property itself, and the need for important repairs. But often the money needed to keep up a building, might be used for other purposes. A Juristic Person (elected by the condominium owners) with staff will usually manage the building, with help from real estate management companies. Management of a building may often change, with as a side-effect that there is less long-term planning and management. Some unit owners will refuse to pay maintenance fees as long as they do not live there themselves. This of course is illegal, and reduces the money available for maintaining the building. From our experience, it is very difficult for a Juristic Person to force people to pay their dues.

Expect to have little control over what happens around your property. A garbage dump or a slum may develop just around the corner. Zoning is generally pretty lax in Bangkok.

When you lease property for a long time (like 30 years or 99 years), you may save some money when signing your contract, that is, a lease for 30 years may be cheaper than buying property. However, you should be aware that you forgo the rights of owning the property. For instance, you will not have voting rights in annual meetings. How the condominium is managed will be decided above your head. Monthly costs (like electricity) will also be charged, without you having control over it.  Electricity costs and maintenance fees may go up over the years slowly but relentlessly.

If you decide to build in an outlying area, you may have to deal with the 'village headman', an influential figure who may have some sway over the suburb where you plan to build. Expect them to show up at the your doorstep demanding some sort of fee for an obscure building law.

If you buy with the idea of renting the apartment out to make a profit, you may want to think again. In the West, the standard rule-of-thumb for value/rental is around 100-120 times. In Thailand value of property is generally about 200 times the rental price. In short, it’s not a great investment.