Online appraisals

Just a reminder: I don't do appraisals. I'm not qualified and I don't have the time. But I will help you find the experts who can give you solid information about your treasure.
Collectingchannel.com offers appraisals for a fee. They were recommended by Patented-antiques.com, a site with a lot of information about patented antiques like tools and sewing machines. The site offers a handy United States Patent Date Chart to help you date items patented between 1836 and 1965.
If you are planning to sell, or want to verify an antique's value for insurance purposes, you should get an appraisal by a qualified expert.
If you just want to know how much your find is worth, you can do a lot of the legwork yourself.
Price guides and source directories like Maloney's Antiques and Collectibles Resource Directory point you in the right direction.
The fastest and easiest way to see what your item is selling for on the global market today is to do a search on eBay . The online auction powerhouse has changed the market by making items more available, and has kept prices stable.
Some say eBay has lowered the value of certain items, like Depression glass, by saturating the market. But I think it just made items more available to collectors who don't live in parts of the country where the glass is plentiful. Same with other collectibles that are easy to find in some areas but scarce in others.