When making an offer on a house it is customary to make a "Good Faith Deposit" There is no set amount as to what that amount needs to be. Consider this, say you are selling a house and you get to very similar offers. The big difference is that one has a GFD of $20 and another has a GFD of $10,000 all other things being equal, which would you accept?
So the answer to your question is what ever the seller will except.
We have found in San Diego that 1-3% is customary and usually 1% is fine, unless the property is a lower priced property and then 2%. Called EMD earnest money deposit which is held by escrow. Remember that the deposit amount can be countered by the seller when the offer is received. Hope that helps. In real estate every situation is unique.
Congratulations what a great time to relocate and buy a home!!! One % of the offer price on a home offer is considered common. These monies are held by escrow through the closing process once your offer is accepted. Let me know how else we might be able to help, excited for you!!