I have shops on both Etsy and Folksy as well as my own website.
I have more sales on Etsy as I find their site far easier to use and I love the stats page so I probably spend more time on there updating and tinkering about.
My sales on Etsy are worldwide and I make sure the listings have postage charges to cover this. I also have several overseas repeat buyers.
I have just moved over to a Folksy 'plus' account so will see how that goes.
All my folksy sales have only been to the UK ( I have also had 3 non payers on folksy - but thats just annoying rather than a loss).
NOTHS charges about £700 joining fee, so that would put me off - how many sales would you need to do to recoup that outlay?
WowThankYou works on the same principal as NOTHS but charges about £35 joining fee.
I have seen a big rise in my sales by prudent networking and stealth advertising.
It all takes time and effort but the bumper months are definately Oct, Nov and Dec - and Jan when I have a sale to sort my stock out.