Hi, I am in a small town, (18k) and am having a hard time finding comps. Can I use the city’s assessed value search: http://www.wirapids.org/Assessor/search.php
Thanks!
VSD
The Tax Assessed value is usually below true market value. That of course varies from place to place, but in San Antonio it is 15% below as rule of thumb.
There are some online sites that offer comps as part of their system, but they cost money and they range I would guess from $50 to $200/month. These also vary depending if your state is a full disclosure, or none disclosure state 
For example, I cannot get true comps online in Texas. That is why I have my license.
From your question, I would assume you aer just starting out. Try one of the http://www.myrealtydata.com or http://www.firstamres.com I think the first offers much more for the price, but shop around and see.
Why not add a realtor to your team to get your comps?