You may be asked to pay a reservation fee while the landlord decides whether to accept your application for a particular property. The most the landlord can ask you to pay is one week's rent. They must give you a receipt.
Only one fee at a time can be held for a particular property.
If the landlord accepts your application, the fee will go towards the rent starting from the first day of the tenancy agreement.
If the landlord does not accept your application, they must refund the fee. This also applies if they have promised to do certain repairs and do not, or if they change an essential term of the agreement (e.g. the amount of rent) and you do not agree.
If you decide not to rent the property for any reason, the landlord can keep part of the fee for rent they lost while you reserved the property.