The Microsoft Xbox store has a 70% off sale on Forza Horizon 5 & 4 Premium Editions Bundle which can be used on Xbox or PC. I was about to pay full price for just Forza Horizon 5 standard edition yesterday, but fortunately this deal came up which worked out even cheaper than getting standard edition.
You can also buy these other Forza Horizon game editions on discount, but the 5 & 4 Premium Edition Bundle is much better value if you don't own Forza Horizon 5 or 4 already. The premium add-ons or upgrade bundle is probably the best one to get if you have an Xbox Game Pass since it includes Forza Horizon 5 & 4 standard.
Forza Horizon 5 Premium Edition: 50% off - $74.97 (was $149.95)
https://www.xbox.com/en-AU/games/store/forza-horizon-5-premi…
Forza Horizon 5 Premium Add-Ons Bundle: 50% off - $34.97 (was $69.95)
https://www.xbox.com/en-AU/games/store/forza-horizon-5-premi…
Forza Horizon 4 + 5 Premium Upgrade Bundle: 65% off - $48.96 (was $139.90)
https://www.xbox.com/en-AU/games/store/forza-horizon-4-5-pre…
Note that Steam has Forza Horizon 5 on sale for PC too, but the prices on Xbox store is still cheaper. Steam does have Forza Horizon 5 standard edition and deluxe edition on sale for 50% off which is not available on Xbox store.
https://store.steampowered.com/app/1551360/Forza_Horizon_5/
Absolutely loved FH 4, got bored with FH 5 quickly. Bigger map but environment design is tedious and lacks the amazing seasonal environment changes of FH 4.