https://www.notebookcheck.net/New-Xbox-handhelds-may-cost-EUR599-EUR899-as-ROG-Xbox-Ally-and-Ally-X-price-and-release-date-leak.1036184.0.html
The Pro/X model is rumored to cost $800 (€900 for yuros because fuck them). The base model will cost $500/€600.