Legit as a purchase
You pay at a checkout that shows the price first, names its delivery method and refunds on request within 21 days. In that sense the sale is an ordinary one.
Read before ordering
Buying coins breaks EA’s rules. This page says what that means, so the choice is an informed one.
Today €7.06 per 100K on PC
The rule
EA’s guide to playing by the rules is short on this point: do not buy coins; getting them from a third party breaks the rules. The User Agreement adds that in-game currency has no monetary value and may not be sold or traded. Comfort trades are named as something that harms the game economy.
The penalties EA lists can apply from the first time: removal from leaderboards, removal of coins, deletion of the club, a block on the Transfer Market in the apps and on console, and temporary or permanent bans from online play.
Two meanings
You pay at a checkout that shows the price first, names its delivery method and refunds on request within 21 days. In that sense the sale is an ordinary one.
No. EA does not license coin sellers and treats every purchase from one as a breach, whoever the seller is.
Claims
It can cover your money: a visible total, a receipt, a refund window. It can cover your account against strangers: backup codes used for one delivery and replaced afterwards. It cannot cover EA’s decision, because no shop takes part in it.
Shops that promise more than that are describing a wish. We prefer to say where the line is.
Looking for approval
No. EA has authorised community sites for squad building and market data, and players link their accounts with them. None of these sells coins, and EA’s rules make no exception for any seller. A badge claiming official approval for coin sales is invented.
Buying anyway
The order itself is walked through under best site to buy FIFA coins.
Delivery
Coins cannot be sent from one account to another by any official route, so a delivery is always a workaround. Here it is Comfort Trade through the Web App, within 2 hours. Keep the club closed while it runs, replace the backup codes when it is done, and look at the trusted devices list in your EA security settings.
These steps protect the account from misuse by others. They do not change how EA regards the coins.
Straight answer
There is no method that rules a penalty out, and any guide that claims one is guessing. EA does not publish how it detects purchases, so nobody outside EA can tell you which amount or timing is unnoticed. What you can control is smaller: order no more than you need, keep your account details to the one delivery, and check My Penalty History if anything looks different.
If that is a price you accept, the form is at the top of this page. If not, earning coins in the game costs nothing but time.
The rules are above, the price is in the form.