Finding Value Of USSR Cancelled Version Collector Stamps

There has been near 30 years pause in my stamp collecting and right now I feel like total newbie when trying to get any information about my collection.

ebay has many USSR stamps and approximate price but there is much less info for collectors issued cancelled sheets.
Do these USSR cancelled sheets for collectors have lower or higher price?

For example I would be grateful if someone could give me some hints where and how to find value of ebay item 371827188929 (link below), when this 5 stamp stripe is cancelled:
(3 post stamps in lower part of stamp stripe, only upper part of date, most of numbers is left off and date not readable. Bought 1991 from philatelist shop)

Sergii-Radonezhsky-Troitsa-Russia-Russian-Soviet-Union-5-joined-stamps-1991-Rare

https://www.ebay.com/itm/Sergii-Rad...AMXQltxQ4-QJ

Robertan,

the stamps in question are Scott # 6004-6008, the strip being 6008a. Priced at $3.50 MNH and $2.50 used, one would not characterize it as "rare" - the seller you mention has it hugely overpriced. From your description it would appear that your strip is cancelled-to-order (CTO), so the catalogue price above for used should be further reduced.

The Russian specialized catalogue of Zagorsky has the used strip priced at only $0.30, probably a better indication of the true state of affairs.