I recently had a question posted on Linked in saying "I have some antiques from my relatives who have passed away. How do I research to find out what they are worth? Help!"
There are a lot of ways to get a valuation, if you know what you have (for example, you know you have a Lalique vase, and a Fenton Ruffle Bowl, etc) you can research sold lots for free in eBay's advanced search tool. eBay auctions can be all over the map though. I recommend you might also search for sold and live lots for free at www.liveauctioneers.com.
Sometimes local museums or swap meets will have free or low cost appraisal days, so I would look into those in your area to see if any are coming up.
If you have a lot of items and you aren't sure what you have, hiring an appraiser might be the best thing to do. If you decide to hire an appraiser to come take a look and tell you what you have, you can find appraisers at The Certified Appraisers Guild of America, The International Society of Appraisers, and The American Society of Appraisers.