I believe they have purchased those accounts at a lower level in the first place - a bit like your $6.95 account. To get a $6.95 account from Enom now would cost an upfront payment of $6995, you bought yours from someone else but it wasn't new - and Enom have raised their minimum price to $8.95 for all new accounts since then.
To have an account at $7.95 etc you must have picked it up much earlier, or have bought it from someone who did.