There seem to be some provider with special offers regarding some domains. For example I just did a quick search on the internet and found a provider offering a .de domain for 5 Euro, but on the other hand their .com domain cost 19 Euro per year.
So if you really spend time searching you may find some special offer that will get you a domain a few dollars cheaper, but those providers then have other drawbacks, since they have to make their money somehow as well.
I would not spend that much time into a topic that could me potentiall save a few dollars per year, I spend significantly more on other things.
Here I found a comparison chart of the cheapest: https://www.domcomp.com/
GoDaddy gives you .com for 0,99 cents, but if you read a bit it is limited for one domain per customer, and 1&1 also gives you a .com for 0,99 cents, but it seems just to be a welcome offer for new customers etc.
So there is always a drawback somewhere, better not be to greedy and eventually get some contract with extra costs you do not get rid of again, I prefer just to pay the regular prices and not get any bullshit with it.