For those of you using eBay's File Upload, what program do you use if you're not using Excel?

After a long hiatus, I've decided to start listing on eBay again. I see that now there's a way of creating listings using Excel, but my Excel is the 2007 version, and it's not up to the task. (Tbf, eBay does warn that older versions of Excel may not work — and they're absolutely correct.)

So what free spreadsheet program(s) are you guys using to create listings? Are you having any issues with these program(s)? Is this really working for you?

Before anyone suggests it, let me assure you that I'm not interested in a third-part listing program unless it's free (and if it is, how are they making any money?). In fact, the reason I stopped listing on eBay was the deprecation of TurboLister, when it appeared that we'd all have to find a third-party listing program to bulk list. I chose to stop listing instead.

I would very greatly appreciate any advice, suggestions, and/or help that you could give me as to how to I can bulk list these days. Thanks so much in advance!