I'm unclear as to the specific connection between a sold or lost item and a lost friendship. Without the details of what happened, its hard to answer your question accurately. It sounds like you were low-balled on a item you thought was worth more, but needed the money...? If so, don't feel bad, most of us have been there at some point in our lives.
To me, collecting Archery and hunting
memorabillia (Bows, guns, knives, sporting books, magazines, etc), is a personal thing. The item in question, at that given moment, is worth what I am willing to pay for it. I may pay more, or less than another person would, for a specific item. A special picture or fishing lure, that kindles a specific memory or emotion, is worth more to me than an item that doesn't. Ever hear an old song and remember a girl or state of mind from a certain time in your life decades ago? Ever catch a wiff of something or a taste, a flavor, and it sparks a childhood memory? I like red and black plaid wool jackets, as my Grandfather's wore them. The same goes for cigars and Apple pie. I don't just love the taste of the smoke and pie, and the feel of the wool; they are a link to my past, a past full of people who's death's I still mourn.
I suspect for most of us, we aquire and collect items that serve as a connection to our past, and as a link to our future. As we grow older, we come to understand and accept that our days are numbered, but we still desire to cling on to positive experiences and emotions. We HOPE that our children will also cherish the same items and values, but once again, individual percerptions are just that... individual. I wrote an article a while back for TBM ("Remnants of the Hunt"), on this topic, after I purchased another bowhunter's mags and pictures on E-#%$. It can be a somber topic, a reminder of our own forthcoming demise.