For cold / glacial backups, M-disc will run you $200 for 10x 100GB discs, plus around $300 for a pair of USB Blu-ray burners. With that, your data up to 500 GB can be written in duplicates and stored at two physical locations (one drive at each location), with very strong guarantees that it will be readable far into the future.

If you write 2 additional disks per year, this is a $500 initial investment plus $20 per year. Compared to Google's "AI Plus" plan you break even in year 5, assuming Google keeps pricing flat.

Of course you don't get any cloud access or similar.