First of all, being a Lord doesn't make you royalty. All royals are lords, but not all lords are royals.
You can't actually buy titles, no matter what any website says. They're all elaborate scams with confusing explanations of copyhold and copyright, designed to fool gullible people into parting with their money for a fancy-looking sheet of paper.
Peerages cannot be sold due to the 'Honours (Abuses of) Act 1925' which expressly forbids the sale of titles. The only 'title' you can buy is a Lordship of the Manor or Scottish Feudal Barony or Earldom. In these cases, the buyer is only John Smith, Lord of the Manor of London, John Smith, Baron of Skye or John Smith, Earl of Arran respectively.
Moreover, there is no such title as Lord. Lord is a styling of Peers or their sons, for example:
The Duke of Edinburgh is Lord Edinburgh in conversation.
The Earl of Wessex is Lord Wessex in conversation.
The son of a Duke or Marquess is entitled to the style of Lord John Smith, but this is a courtesy title and not held in his own right.
These 'Seated titles' are just hogwash. The idea is that you buy a centimetre of land and become Lord of it, which is unfounded and silly.
Also, if you're American, you cannot hold a title of nobility under US law, which outlaws Americans from using, claiming or granting titles of nobility, lest they lose citizenship.