There is no rule dictating a minimum earnest money deposit when buying real estate. Usually, all Florida contracts call for 2nd earnest deposits: The 1st deposit is minimal (from $1,000 to $5,000 and even more for mega mansions). The 2nd make up about 5 to 10% of the purchase price depending on the price of the house (1st deposit + 2nd deposit together equaling 5 to 10%). The protocol is to offer a strong first and a strong second earnest deposit. By doing so, you are sending a firm message to the seller that you are really serious about buying his/her property.
However, you can make an offer with $0 deposit if you want but a seller would most likely not even consider your offer. Rarely (but it is known to happen once and a while), a seller will accept an offer presented with $0 down but there would be a stipulation in the offer that if the seller accepts the offer, then buyer will have 2 to 3 days to come up with a strong deposit. Or, if you put down, say, a minimal 1st deposit and no 2nd deposit, again, you show the seller that you are financially weak and seller will think twice and very hard about accepting your offer--but if this is all you have to put down, there is nothing you can do about it.
Other buyers who really want a property are very confident to buy that property, they put only one deposit but it is the full 10% down.
Remember that real estate is not a charity event and sellers may sympathize with you but for their own sake of selling their property, they don't want to take on a weak buyer.