If you are not comfortable with the price and they will not take your top price...let it go.

I collect nothing but Hotel Thunderbird items and I have passed on at least 30 items in the last few years due to sellers perceived value of their Thunderbird item and mine were just to far apart to make a deal. I have been outbid on at least 35 Thunderbird items on Ebay.
Most items that I missed have not resurfaced on Ebay again. Would I like to have everything Hotel Thunderbird I see, Yes, but I set my personal value to each item and do not exceed that amount. Would my Hotel Thunderbird collection look better with all those items I passed on, absolutely. I am not including chips since there is a guide to give folks a starting place of value. I have all the Thunderbird Chips I am going to get since the remaining ones on my want list are just priced to high. I would like to have them but I sleep just fine not owning them or the other items I have passed on.