Ooooh thank you SO much for your help! So I believe it shouldn't weigh anymore than 30 grams (in an 8 inch x 10 inch envelope). So I THINK if I'm understanding correctly, it'll fall under the "large letter" category, and cost around £1.88 to mail back to the US, in which case 4 second cla...

Hello! I'm hoping I can get a bit of help. I live in the USA. Previously, I mailed a letter to an actor in the UK, and on my SASE I put 4 second class stamps (I'm a newb, and that's what a seller told me would work). It was successful, and I received a reply soon after. I'm looking to send a letter ...