Things usually thought of as closing costs are real estate transfer fees or taxes, title insurance costs, and some document preparation and filing fees. Those for a
DVC timeshare can range from just below $400 to $500 depending mostly on the title companies you are dealing. Those are mostly fixed and vary only in minor amounts whether you sell 1 or 1,000 points. Who actually pays them (or portions thereof) is something that should be spelled out in the contract of sale.
Other closing money transfers will be any commission the seller must pay to the broker, any amounts the seller still owes on his loan if he has one, and whatever has been agreed to as to dues. When you close, dues not yet paid for the calendar year must be paid in full. Also, if seller has already paid all dues for the calendar year he may feel entitled to a payment from the buyer for at least the amount applicable to those months in the calendar year that the buyer will have the property. Generally, exactly who is going to pay what in relation to dues is something that should be agreed to in the sale contract.
Note to above -- sellers don't necessarily pay a 12% commission to a broker. In timeshares, brokers often have a set fee ranging from $1,000 to $1,500 as a commission (and thus your percentage can be much lower than 12% or even much higher depending on how large the contract actually is). Brokers may also negotiate on what their commission will be.