Also, if
@ScotIpswich is willing to invest a small amount of money into his collecting, a quick look on eBay will find many TfL Oyster Wallets. I bought one with some relatively old Tube Maps.
I've just done a quick eBay search and these are a few of my finds:
https://www.ebay.co.uk/itm/RARE-one...569002?hash=item1ef9a833ea:g:kg0AAOSwnCdcULCv
It is a ONE Railway Season Ticket Wallet. It hasn't been used, judging by the photo. It seems to be in an unfolded state. It's a Buy-It-Now for £1, and considering it's from an old TOC that seems to me like an alright bargain.
https://www.ebay.co.uk/itm/One-Orig...862275?hash=item46958e9d43:g:HA4AAOSwuJRb-oYV
This is just a standard National Rail wallet, but if you are just looking to collect some it could be interesting. £8.49 Buy-It-Now, so more expensive than the ONE wallet, ut still a wallet!
https://www.ebay.co.uk/itm/4-BTP-Tr...741387?hash=item4695f794cb:g:0I8AAOSwcydc5Xzu
Some BTP wallets. They come in a set of four (all seem to be identical) and they are an Auction, currently at 99p. I suppose that you could always just sell any extras if you went for this one.
https://www.ebay.co.uk/i/113715735288?chn=ps
And this one is two Oyster wallets (black, not the normal blue with the cards pattern). It seems like an interesting one and seen as you get two £2 seems to be an alright price (Buy-It-Now). As with the other one, you could always sell one if you don't want it.
-Peter