Quick question about posting a card!

[TheBadElfParade]

It’s my friends birthday next week and I have a flat keyring and a card I want to post out (U.K.) Will I get away with putting the keyring inside the card and sending it off in the postbox in the envelope??
Or will this have to be packaged and paid for at the post office?

I’m trying to avoid another trip out if I can help it but I’m clueless about Royal Mail

Thanks

Large letter stamp will probably cover it.

If you go on the post office website they give you weights and prices etc. You can even print stamps off.

You should be ok. A normal stamp is OK for items up to 100g and 0.5cm thick.

www.postoffice.co.uk/mail/uk-standard

or if not...you can buy postage on line and print the label. sounds like the pack will still fit in a postbox so you don't have to go into a post office. (which if it is anything like my village shop is superspreader central!)