I have been trying to register 2 letter domains for very long time now however I can't find a place to do it.. In every domain search I put 2 letters it comes INVALID..
What domain extension? Most of the newer ones like .BIZ, .INFO,.US don't allow two-character domains. .ORG now retires two-charater domains when they drop. Two character .COM and .NET domains are allowed, but are all highly valuable and sought after of course.
If you don't care about the extension, you could register a two letter domain in a country code like dot VC.
not at all, there are over 300 extensions, you will find one. However, some of them cost a lot. I have even found a one letter domain before, but it was 400 euros to reg and I just don't have that kinda cash.