Do you think Microsoft Excel is worth purchasing?
That's not a question I can answer for you. There are alternatives that are free, such as Google Docs or Libre Calc. For the casual user who will be constructing simple spreadsheets, either may be just fine, especially when you consider they can be saved in relatively universal formats, such as .csv or .ods.
If you have designs on becoming a moderate to advanced architect of spreadsheets, the decision gets harder.
You will have to ask yourself more questions, like:
Will I be sharing these with others?
Will they be editing them?
Am I using their spreadsheets, were they constructed using excel and do they have complex formulas or VBA code that might not work in my open source or free program?
Ultimately, the answers to these and similar questions will tell you whether or not it's "worth it".
I would not buy Excel as a stand-alone application. However, I would definitely encourage you to subscribe to Office 365 that includes Excel, Word, and PowerPoint among other applications. I have an Office Pro subscription that also includes Microsoft Access.
You can run any application on up to 5 machines and all upgrades are automatically available. I found the subscription to be reasonably priced and don't have the worry of "owning" an obsolete license.
Yes, there are "other" free application suites that claim to offer similar features although that has not been my experience. However, when it comes to business, Excel is the prevailing spreadsheet application - at least in my domain.
Yes, if you need s spreadsheet. It's simply the best general purpose spreadsheet and remarkably powerful for most data analysis
There are lots of website available that will offer you free Excel Tutorial for beginners. From these websites, you can learn Excel basics to Advanced excel