I know one requirement is being able to set it up on wunderground.com.
... and weatherforyou.com and CWOP.

To keep it around $200 you could go with a basic Oregon Scientific unit which would leave room to purchase most of the software listed in this forum, or a more advanced Oregon Scientific station and FreeWX. If your budget could go to around $250 or $300 it opens up many more options.
What a great son!
