Official Goldback.com exchange rate for 10/09/2023 is $3.98, up 2 cents from Friday.
Best prices:
1 GB is 3.64 (check, also you get a free SD GB with purchase of SD series goldbacks)
http://defythegrid.com/goldbacks/ref/6499/
1 GB is 3.68 (credit card)
https://finestknown.com/goldbacks-for-sale/
50GB is 181.31 at APMEX