In that price range, only two models of the Palm Zire are available...the Zire 21 and Zire 31. (For a full comparison of all Palm PDAs, click here)
The $99 Zire 21 has just 8MB of built-in memory, and lacks an expansion card slot. Thus I'd recommend against it, as it probably won't take long before your husband runs out of room.
For an extra $30, you can step up to the Zire 31, which has 16MB of built-in memory, and that all-important expansion slot so that you can increas its storage power up to 1GB! Plus, its color screen and faster processor more than make up for the extra cost.
However, neither of these models comes with built-in support for Microsoft documents. For that ability, you'll have to purchase the software suite ''Documents to Go: Standard Edition'' (Word and Excel compatibility) at $30 for the Zire 21, or ''Documents to GO'' (Word, Excel, and PowerPoint compatibility) at $50 for the Zire 31. I believe you'll also have to purchase a third-party program (such as Beyond Contacts for $30) for the ability to use Outlook.
All totaled, you're looking at $159 for the Zire 21 or $209 for the Zire 31.
For around the same price, you could pick up the Dell Axim X30 ''low'' for $199 (with 15% off sales occurring frequently). It runs WindowsMobile, and has built-in support for Microsoft Word, Excel, and Outlook. Plus, it has 32MB of memory, a much faster processor, and better support for multimedia.
Note that all three of these devices use older versions of their respective operating systems, and are all headed for ''retirement'' soon. However, tech support will remain for the full length of the warrenty. (And you could always ask us, too. ;))
Hope this helps,