I will give my opinion since it looks like a scam.
DDOS protection for 25€ ? I mean, how do you expect to block a small ddos of like 500k pps with 25€, you will have to explain it briefly. In production mode, to be able to manage with a firewall solution "Home made", so a Linux box with dedicated rules and kernel acting as a proxy shield, with a dual xeon 5600 series, it couldn't stand a shit, and a cisco guard can barely stand 400k pps on a port and then it will create multiple short loss.
To complete to post gaven on the top about the ddos and the analogy to block the packet if the ip is blacklisted, you can send a packet with a fake ip source and generate it like you want, yeah you get the fun ? blocking an ip is useless you got it, but I guess the guy who posted knows it since he seems to have knowledge in that field.
To make it brief, your solution is a bullshit, I am pretty sure you call "ddos protection" installing apf and setting up iptables. Your replies and post just show your lack of knowledge and your immaturity. I strongly recommend you to do not trust that seller.
Now, if someone really wants to pay for some ddos protection, you should take a look at some company , just google it, for a decent protection against small/medium dos/ddos, you have to use aprox 500$ per month which should make you free against most of the wannabes that get shellbots and people that own few vps/dedi.