As reported by Axios Gaming’s Stephen Totilo, Microsoft claimed that the handheld will have a price below $300 in a filing made before its scheduled hearing with the FTC. However, the claim has no further context or factual support to back it up and hence cannot necessarily be taken as completely accurate. On the other hand, the $300 price for Sony's Project Q does make sense when considering what the device does.
Microsoft claims that Sony’s upcoming handheld, codenamed Project Q, will cost less than $300. This was revealed in a filing presented to FTC