There's no average. Everything is negotiable.
The earnest money has to be something acceptable to the seller.
Always remember you're trying to make an attractive offer and every detail counts.
Not just the earnest money.

can't imagine why anyone (other than a fabian fan) would give a thumbs down to elvis on this one. i see contract on properties all around the city and surrounding suburbs. some still go as high as 10% (!) of the purchase price. most still use 5%. a great many simply put down $5,000 or $10,000.

sorry for the repitiion in this answer, but if i were a buyer, i'd put down as little earnest money as i could possibly get away with.

were i a seller, i'd want to see 5%, but if the buyer appears to be serious and well qualified, and price offered were fair, i'd take less...

North Shore here too...

Typically $1,000 with offer for initial earnest money deposit. And while it used to be 5% in "boom years"... If I'm acting as buyer's agent... I recommend as little as possible... sometimes 1% or 2%... of course, if I'm the listing agent, I'm looking for closer to 5%... but we're seeing deals gel for far less than 5%.

Alonzo,
In Chicago the average amount of earnest money is 5%. Of course there are variations, a home that I recently sold for $900,000 transacted with only $15,000 in earnest money while another home that I sold for $1.5MM had only $50,000 in earnest money. As the previous respondent indicated, an initial amount of $1,000 or so is expressed upon the execution of the contract and the remainder is agreed to be expressed at a set time often linked to attorney review/inspection period.

Best of luck with any searches or sales that may be on the horizon for you.

Here on the North Shore, an offer is usually accompanied by a check in the $1,000-$5,000 range. The balance of the earnest money - usually at least 5% of the agreed on purchase price - is typically paid within 48 hours of satisfaction of attorney and inspection issues. However, these are issues that decided on between the parties - it's up to the individual buyer and seller to come to an agreement on terms.