Change existing acct from IMAP to POP

I set up my email in Thunderbird using IMAP but ran out of disk space on the server (DreamHost) even though I only have 583 total emails. I was told to change it to POP. I can’t change an existing account so I have to setup a new one and according to directions, it says to move all sub-folders (draft, sent, old etc…) into the inbox BEFORE I setup the new account. Are all the sub-folders going to be mixed in with the inbox and not distinguishable from my incoming emails? Is the correct way to change from IMAP to POP is to move all subs into inbox>create new account and setup as POP>then remove the IMAP account from Thunderbird? Will this clear up my disk space on the server?

Why not just remove the limit on disk space? Go to your DreamHost Panel, click on Mail, then click on Manage email. Then click edit next to the account(s) you want to remove the limit from. Then remove the check mark from Limit total disk usage. Finally, click on save changes.

Does DreamHost charge more money to either have no limit or to increase the limit on disk usage?

No, we do not.