A description and location might help. For example, a boxing expert might not help you, while you might have a baseball expert two blocks from your home.
Cal Ripken’s Baseball Glove - $10,000 ... Jim Brown’s #44 Cleveland Brown’s Jersey - $20,000 ... Wilt Chambelain’s Jock Strap - PRICELESS ...
I might be able to help you; I appraise collectibles. Just sold some sports memorabilia for a client...who knows...may have been some similar things!
go to heritageauctions.com.
I dealt with them several months ago and they were great. They were professional and did exactly what the said they’d do. Contact them, send them a picture and a description of what you have and they’ll send you a quote as to what they’d sell it for. If you want them to sell it, they will.
I had a letter from Robert Oppenheimer to my Father and it fetched $2400. They do sports as well.
You need to call Chumley in Vegas
First, you could always find the antiques roadshow :-)
Second, there are associations and you can contact them for recommendations.
Third, never - never tell the appraiser you are considering selling. Next thing you know you have lower prices and they, or a shill, are making you a ‘fair market’ offer. If you have no clue as to price, contact an insurance firm and request a valuation for insurance purposes only. You wish to keep the goods and insure them for a fair value in case of damage or theft or fire, etc. You’ll at least know, then, the ballpark of value so you do not get ripped off.
You can also go to a trade show. Like for baseball stuff or whatever. Look around. You’ll probably find identical items. When it comes to some things, though, just because it looks that same does not make it so. Therefore, a lot of homework is needed.