Help a novice BFPO user please!

[DSHathawayGivesMeFannyGallops]

Probably a very silly question but I just want to check this. I usually find MN delivers the goods!

Very dear friend has just been deployed with the Navy and has requested letters, and has specifically pointed out Blueys as easy to send. So having written my very first one, my next question is does it need a stamp?

I was told they're free, googling suggests they're free to send, the PO asked what I usually did (helpful) and looked it up and it seemed to suggest a stamp is needed to send to a ship/this destination, my RN wife friend & her RN DH think they're free but thought they'd gone out with the ark! Can anyone offer a definitive answer or tell me where to look to get one? Even worse, I actually work alongside the military & I'm too embarassed to ask at work . I can always just pop it in an envelope or put a stamp on it anyway... but I kind of want to send it properly, if possible.

Please help!

Free if it's to an op posting as a general rule of thumb. Google the BPFO address and see iwhat the postage charges are.

Alternatively, use eblueys!!

Ebluey doesn’t exist anymore. Google the BFPO number. Some on active duty and certain operations are free. Others are not. If it’s free is doesn’t need a stamp just pop it in the letter box