Super Mario Odyssey $36.01 + tax (YMMV) at Amazon.com with Prime 20% off and AmEx 20% offer (expires 10/23)

Amazon has Super Mario Odyssey for $59.99. Prime memebers get a 20% preorder discount. Amazon is also running a promotion for some members right now that gives you 20% off all items sold by Amazon when you pay at least partially with AmEx points (NOTE: the 20% AmEx deal ends tonight, 10/23 at 11:59pm PST)

My invoice shows

Item(s) Subtotal: $59.88
Shipping & Handling: $0.00
Prime Savings: -$11.89
AMEX 20% Discount: -$11.98
-----
Total before tax: $36.01

The 20% AmEx offer is not available to everyone, but a lot of people seem to have it. If you have an AmEx card with Membership Rewards but haven't added it to your Amazon list of payment methods, it might possibly help to put it in there (and there may be an additional step requires to setup the pay-with-points option, but I don't recall since I did that a long time ago).

This deal works out slightly better than Best Buy's GCU 20% + $10 offer, as long as you are a prime member and eligible for the AmEx offer. It's worth noting that in the Best Buy deal thread, one person reported success getting Amazon to match the $10 offer. Others were unsuccessful. Just for the heck of it I tried to see if they'd offer the extra $10 but got shot down.

Paying with AmEx isn't the best in terms of cashback, but you can actually improve on this price by about $1.80 if you have a Discover Card with the 5% cash back offer activated for Oct-Dec, as long as your current gift card balance is less than the final cost of the item. The steps to do so:

1) Add the game to your cart
2) Go to checkout.
3) change your payment method to pay with AmEx, and the when the option below is available, choose to pay 0.01 of the balance with AmEx Membership Reward points.
4) Go back to the checkout page and get your final price, including prime discount, amex discount, and tax. DO NOT CHECK OUT YET. Remember this price
5) Calculate how much gift card you need. Take the final price with tax and discounts, subtract off whatever your current Amazon gift card balance is, then subtract off a small buffer of at least a couple of cents (or maybe $1 to be safe). Be sure about your math here, as if you go over, you'll need to spend it back down 1st to make this work
6) Reload your gift card balance with this amount. You should now be just a tiny bit short of paying fully with gift card.
7)once again change your payment method. Select your AmEx card as the payment method, choose to pay 0.01 with points, check the box to pay with your $36 gift card balance.
8) go to the checkout page and you should now be charging less than $1 to your AmEx card.