Bright Side of News has details about the launch prices of the upcoming Radeon HD 5700 series, the site says these models may replace the Radeon HD 4800 series.
Radeon 5750 and 5770 are scheduled for launch around the official launch date of Windows 7 [give or take around October 22nd-23rd, depending on what continent you live on]. The prices are set at just 149 US Dollars for 5750, with 5870 being priced at 199.
And here comes the kicker - when AMD introduces ATI Radeon HD 5750 and Radeon HD 5770, all of Radeon HD 4800 series are getting "EOL" [End Of Life] marking, since they will be pitched at same price points [149 bracket has HD4870 and HD5850, 199 bracket has HD4890 and HD5870]. Bear in mind that some e-tailers in the USA might offer a MIR [Mail-In-Rebate], ranging anywhere between 5-15 USD.