Old Collection Of Coins - Looking For Value

I think the best thing you can start with is learning how to use the online price guides of the bigger grading services.
https://www.ngccoin.com/price-guide/united-states/
https://www.pcgs.com/prices/us

The coins that already have official grades will be easy to get a ballpark value. The rest you'll have to learn to judge the grade yourself. Be realistic about it. Your 1877-S 25c in G condition for example shows a value of about $35, but that's retail price. Those worn and common Mercury dimes won't be worth much more than melt value, but if you have a lot of them it can add up. If you run into something that gets into hundreds of dollars in a mid grade, post it separately with good photos and people will help you zero in on the grade and value.

Of the British coins, the large 1937 penny is a common coin that you might find in dealers' junk trays in the UK for 10 pence (12 US cents). The 1976 New Penny and the three 7-sided 20 pence coins are all current British coins that are still legal tender, worth around 75 cents altogether. If you have any friends or relatives visiting the UK, you could give them to them to spend!

Chances are excellent that you won't find anything of significant value.

You may want to consider keeping the collection as a family heirloom. Trying to sell these common coins will probably be more trouble than it's worth.

The prices marked on some of the holders look very inflated. What you might want to do is take photos of each coin front and back and list them separately in the appropriate grading section. Once you have an idea of the grade you can reference price guides to get an approximate retail value.