Does not recommend this product
It looks like my comment from yesterday got removed.
It looks like a lot of these newsletters were copied from BuySellAds and a 10% fee was added on top of that price. BSA is already adding a 30% fee and then Letterwell is adding their 10% fee.
Here are a few examples:
MacRumors
BSA - https://buy.buysellads.com/directory/macrumors/checkout/new - $1,000
Letterwell - https://letterwell.co/newsletter/macrumors/#book-advert - $1,100
GraphicDesignJunction
BSA - https://buy.buysellads.com/directory/graphicdesignjunction/checkout/new - $600
Letterwell - https://letterwell.co/newsletter/graphic-design-junction/ - $660
FreeWebsiteMonitoring
BSA - https://buy.buysellads.com/directory/freewebmonitoring/checkout/new - $950
Lettwewell - https://letterwell.co/newsletter/free-web-monitoring/#book-advert - $1,045
CultofMac
BSA - https://buy.buysellads.com/directory/cultofmac/checkout/new - $1,000 & $4,500
Letterwell - https://letterwell.co/newsletter/cult-of-mac-weekender/#book-advert - $1,100 & $4,950
These are only a few examples. There are a lot more. All of them are EXACTLY 10% more.
Before my comment was removed, @sjs replied and said the publishers all added their own sites. However, that doesn't seem to be the case: https://imgbox.com/vZYDJaS7
This isn't just about the additional fee on top of BSAs fee. Letterwell says the advertiser payment is held in escrow and they have verified all performance metrics themselves. I'm not sure how this works if they are adding these listings and buying through BuySellAds.