Common in the states ( or at least all the books I read seem to suggest )
Less common and easy to execte in the UK. Developers used to 'gift' the deposit to a purchaser for a sale of a property but thats been tightened up to a very large degree.
More common know for a gifted deposit to come from a family member to another family member interested in purchasing the property from one person to another ( mum to son etc )
Can I ask in what context you ask this question? Maybe I can help further , in another life I did uncommon things with property. Feel free to PM me.