Well... I'm going to be the man in disagreement here. There are different ways of doing things, of course.
Just for reference: I'm a sound engineer -besides guitarist, obviously - who has recorded several albums and live performances. I tell you something different:
* Two mics are better than one. Always.
* You don't need to be a sound engineer to make a decent stereo recording: it's a question of positioning the mics well, and there are dozens of decent tutorials.
* The most suitable mics for use in a home stereo guitar recording are the small diaphragm condensers (for many reasons that you really don't need to know), so buy a pair that you like:
- I can assure you that must of the people who advise a particular Mic, will fail irretrievably in a blind test. The truth is that the positioning of the mics, your pulse, the environment, the strings... Everything is much more important than the mics themselves (as long as they are moderately decent).
Finally, returning to your initial question "Affordable mic recommendation
": Well, I'm not a salesman... Taking a look at Amazon
, a pair of Rode-M5 s seems a good price-quality option for your purpose, which doesn't mean that you can't get good results with a pair of Behringer C-4 s, for example (I did it many times).
... And yes, of course: two Neumann KMs are better... But that's not the point.