How much does it cost to put property on the market?

In the UK you usually don't pay anything until the house is sold. Get a few estate agents round to value your place and they'll explain the costs (valuation should also be free)

More details needed! Are you looking to buy the house which is already empty, with the proceeds of the flat you're selling? If so there's nothing you can do until you've sold the flat and of course somebody else may beat you to buying it. If you just want to rent it, you can presumably do that straight away so long as you've got the money for the deposit. If you need to sell the flat to get the cash for the rental deposit, you're still stuck. Estate agents vary in whether they make you pay for advertising in advance. If they do, it's usually a couple of hundred pounds. But if the flat doesn't sell quickly you may have to pay several lots of advertising fees up front. You don't pay the actual estate agent's fee until the flat sells, the solicitor who does the conveyancing will deduct it from the sale proceeds and pay the agent on your behalf. First step, ring several local estate agents and ask them to come and value the flat and tell you what their fee would be, this is normally quoted as a percentage of the sale price but if it is a low value property they may quote a fixed fee. You can also ask then about their policy on advertising fees. Don't just fall for whichever agent gives you the highest valuation, they quote high to get your business but at the end of the day a property is only worth what someone will pay for it, so go with the lowest fee or the most businesslike person.