EQ5 should have come with very well written manual which allows you to teach yourself all the basics and beyond. I started with version 5 and taught myself out of the manual--it's very well written and produced. If the manual is missing, try looking on Ebay or Craig's List for one or see if the company has one you can download for a small fee.
Even if you can't find the manual, it seems you're hesitant to purchase the software upgrade. If that is the case, then you shouldn't because you will be unhappy having spent the money.
However, if you find yourself itching to design your own quilts, audition your own fabrics into an existing pattern, re-sizing a design or auditioning quilting motifs, this software can be MEGA useful!
If you think you'll just be an occasional user, however, I see no reason to upgrade, as EQ5 should be able to do most of those functions, possibly excepting the last one.