Confused with Dropbox. Can you clarify some things about syncing, storage and accessing my account?

Yeah, using Dropbox is hyper-confusing to me, as is figuring out the costs for their other products (and why they exist - eg. Dropbox Transfer? What?).  I don't want to take the time to figure out anything other than to put data on a cloud solution and move it back and forth between devices and third parties.  Dropbox products are just weirdly confusing, and I don't want to invest the time into figuring out what they are trying to sell me.  Seems like they should make it seamless and intuitive in one product solution that makes my life easier.  If they ever make it simple and reasonable, I might subscribe.  I'm a free account and don't really use it that much.