Tl;dr: I did not notice the BTC price they apply is ~ +8% (Compared to coinbase is ~ + 10% in this moment). Other figures are right but the base price is the ~ 8% higher. Sorry!
Long story short: ID + selfie + DNA etc. etc. payed with CC. They charges 3.88% on the amount in $ or EUR + 0.001 BTC when you send them away.
So if you invest 100 $ you spend 103,88 $ + 0.001 BTC, the latter is fixed, so hight BTC price = you spend more, low BTC price the opposite.
Those 0.001 are the only fee to pay to send away BTC. 3 blocks to get confirmation.
All in all: fast, simple, not so expensive after all, if you can stand the idea of selfie with ID and so on.
Using bank transfers lower the 3.88% fee to 0.90% if I remeber well.
Any suggestion is welcome... to be honest I took a look to localbitcoins too, the opposite way of doing things, but here the market is quite poor of vendors.
I hate coinbase so much