Timeshare resorts sometimes offer free lodging to potential buyers in exchange for their attendance at a presentation about properties the developer has for sale. A free Vacation Certificate may be offered by telephone, mail, or from the Internet. Offers vary, but they are often for a three day, two night stay at the resort itself or a nearby hotel. Nearly all offers are subject to certain conditions, including age and income requirements. Both spouses must usually attend a sales presentation and upon arrival participants are often asked to provide proof of identity. Advance deposits, which may not be refundable, are often required to guarantee the time. Any charge termed a processing fee is probably nonrefundable. If deposit funds are actually called a deposit, refunds may be given at the location or at the end of the stay.