First of all, an estate agent a person who is specially trained and qualified to sell houses for either the individual owner who they have agreed to represent or for a professional firm of estate agents. Basically, this involves showing a property to possible buyers -normally estate agents work from their own, or clients homes-, marketing the property, drawing up a price range and agreeing a sale price with the intending buyer -then dealing with the accompanying legalities.
An estate agent also has a network of contacts within the industry -nearby solicitors and surveyors, mortgage lenders ect, and will be able to offer such advice along the way.
Estate agents salary, which is often dependant on commission, can vary considerably but typically the rate of commission varies from 6% to 12% of the sales price, with 10% most common.
Also, the propertys asking price is also the price for which the sellers would be prepared to sell a property, and the most recent accepted offer to buy a property, or the fixed price at which the estate agent is agreeing that they want to make the purchase.