UBB.Classic doesn't have spellcheck, however you can add it in from the mod at UBBDev here

As for the conversion to threads, I think the $75 is just for member area renewals. Besides, once you decide you want to convert, be sure you want to; i myself hate how threads look :/

I am a Web Development Contractor, I do not work for UBBCentral. I have provided free User to User Support since the beginning of these support forums.
Do you need Forum Install or Upgrade Services?
Forums: A Gardeners Forum
UBB.threads: UBBWiki, UBB Styles, UBB.Sitemaps
Longtime Supporter & Resident Post-A-Holic
VNC Web Services: Code Modifications, Upgrades, Styling, Coding Services, Disaster Recovery, and more!