Official Goldback.com exchange rate for 08/25/2023 was $4.01, down two cents from the last update.
After a review of online sellers' prices, the best price for an in-stock 1 Goldback is $3.67 over at Defy The Grid
https://defythegrid.com/product-category/gold/aurum/goldbacks/
The best price for an in-stock 50 Goldback is $176.39 at APMEX