Any registrar offering lower than those, usually has an evil intention to rip you off with a catch.
With respect, not always. There have been a bunch of transfer offers that have been legit, although some have been better than others.
The best that has no "gotchas" has been
@AlpNames - they have done $4.99-5.99 transfers for dot COM and they have standard $8.75 renewal, and zero issues if you want to transfer away, excellent support, active here on NP also.
Next best is likely the domfam - Domain/MyDomain/NetFirms/Dotster. Regular price is $8.29 (dot COM) and coupons often work for prices around $6.22 or better, the best having been 35% around twice a year. Then they had a glitch during one of their promos and a bunch of us caught transfers for $1.69 and more recently $3.19. The renewals are $11.99 up to $18.99 however, we figured out how to transfer hop again before this happened. Also there were no issues with transfer away. They take some effort to learn the tricks to save money, yet the huge savings are worth it.
The deal that is no more was NameCheaps Move Your Domain Day, which occurred in 2013 14 15 16 and never happened in 2017. They had a limit and the prices were $4 plus ICANN, and you could only move a domain there once, if you left and tried to return with promo it was invalid. NameCheap has sorta normal renewal prices, around $10 with coupons. I have never renewed there LOL
Rebel did a couple transfer promos for $1.99 - $5.99 then they started putting all kinds of restrictions on it and they have a bunch of weird gotchas - auto renew 45 days ahead and difficult to turn off, and they make it difficult to update and get Auth Codes
There is one more day on LCN free transfer (limit one)
https://www.namepros.com/threads/free-com-net-or-org-domain-transfer-at-lcn.1024611/
Overall, watch this thread for transfer deals - we have enough members there to warn you off any gotchas!
https://www.namepros.com/threads/8-...scounts-for-com-transfer-renewal-only.985708/