UK SASE postage help

[Hey, Hey You!]

I've seen multiple other posts about sending from the U.S. to U.K. and every post seems like it has different answers on how much postage to put on an SASE and whether to use the small 1st class stamps or large 1st class stamps. Before I go about getting British stamps I'd like to know what I should use. Any help would be much appreciated.

[kimmylee]

1st Class stamps are worth 0.60p. 1st Large Letter are worth £0.90

You need to weigh your return item, convert to grams and use the price finder here

[Hey, Hey You!]

Alright, thanks a lot!