Which cross-platform credit card data store should you choose?

Question

Information Security

Purpose: convenient storage of your credit card data.
Criteria:
1. Cross-platform
2. Free
3. Password protected
4. Sink at least through Dropbox
I shoveled a bunch of services, in this regard, 1Password, of course, is a champion, but it's very expensive. Especially now.
Hence the question, what to choose?
To be honest, I thought about an Excel file or a small service in general, but in the first case it is very inconvenient to add and use it, in the second it is scary.
Thanks in advance!

Answer 1

If Excel is inconvenient to use, you can write your own program or make a database in MS Access.
I use 1Password myself. Expensive, but very convenient. I don’t know how now, when I took it, there was a “family” license for 5 users, it was quite profitable.
Of the minuses, except for the price - major updates are paid, but no one forces them to be installed)

Answer 2

KeePass (native on Win, on Linux via Mono, ported to other platforms, for Open Source).
Extra convenience is a great extension for Firefox. There are plugins.