Standard edition
The standard edition is US $24.99 on Steam. At launch the Steam listing showed a 10 percent discount, which made it US $22.49. The publisher’s own launch notice gives the same discount.
Deluxe edition
The Deluxe edition has a list price of US $31.99. At the 10 percent discount it showed US $28.79. It contains the game, the artbook and the soundtrack.
Buying the artbook and soundtrack separately would cost US $4.99 and US $5.99, or US $10.98 together. Buying the standard edition and both add-ons separately would total US $35.97. At list prices, the Deluxe edition at US $31.99 is US $3.98 cheaper than that.
Other regions
The sources give prices in more than one currency, but the cached pages mangle some currency symbols, so this page does not use the non-US figures. One cached Steam page shows a Hong Kong dollar price. That is a regional price, not a US one, and it is not used here.
Console prices
The PlayStation, Xbox and Nintendo store pages load their prices with scripts, and the cached copies do not contain them. This page does not give console prices. Check each store before you buy.
Price history
A price-history site was in the sources, but its page did not load its chart data. No historical low is given here.
What the sources do not confirm
Discounts change. The figures above are the ones the sources showed on the check date, not a forecast.