MLTS - we must have been typing at the same time. EDIT: TWICE! Also I haven't used Thaivisa for ages and can't figure out how to quote your message - a heavy cold is not helping my dimness, but in my defence I haven't use the site much since it was upgraded (last year?) and google isn't helping me (I did try).
I'm in Thailand and have pre-paid DTAC for my phone, so however many baht they charge is the figure I would pay, and that's fine. I really only send messages to my husband who also lives in Thailand; I always manage to forget to ask him to get milk or bread when he goes out ;) As for what I am trying to achieve - I prefer sending SMS by computer (fat fingers) and know I can currently use VOIPDiscount to type them, but then my message app gets a one-sided conversation on it as there is no way to sync what I typed/sent. I've tried many solutions in the 9 years I've been using VOIPDiscount, and this finally seems to be achievable in a way I like with Android Messages. I was just unsure of if/how the messages would be billed; I could see that they are free within US but with no mention of international that I could see. Google Voice page is clearer and lays out the charge to Thai number (at a much higher rate than VOIPDiscount, so have already discounted using it).
I'm happy to do the messaging through Google as it will keep things cleaner, to be honest I haven't looked at the cost of sending an SMS to Thailand in VOIPDiscount for years, I only know the price of the calls to mobiles because I noticed it coming up with a cost instead of free a couple of weeks ago and checked it out.
I think you've answered my only other question too, which was do I have to leave wifi on (on the phone) for this to work. If it automatically bills the DTAC account, the answer should be no, just sync them up every now and again.
Can anyone help on quoting a reply here?