For legit domains that you will need after 1 year, then yeah don't make the mistake of going with Godaddy, Register.com, 1 & 1, etc... It's not worth the hassle. However, for throwaway domains for churn & burn purposes, these promotions are PERFECT! All you need to do is be extra careful during checkout so they don't put you shitty services automatically in your cart and overcharge you, log in their panel and change the nameservers, disable auto renew, remove the CC information and you are done.
For these kind of domains, I also use debit cards that I always keep with very low amounts of money, like $5 tops (minimum limit at most banks) and have disabled overdraft in the bank accounts, so even if the registrar decides to go wild and auto-charge my card, they can't, because there is no money in it!
I usually buy 100-s of such domains at once from these shitty registrars (Godaddy, 1 & 1 and other promotions from registrars like Register) and never had a problem. Just make sure you cover your tracks and you will be fine.
