Thank you all for the feedback, and sorry for not being aware of the noobie section.
You mention Phantom Power, any AI you get will have that and you can get a very decent device for $150 or so. Look at the Steinberg UR22 , Tascam products, others are by Focusrite, Audient, Presonus and Zoom but these tend to be more expensive. N.B. The cheapest ONE mic input AIs SEEM good value but believe me you WILL regret not paying that bit more for two mic channels. The Behringer UMC range are very good value and SO far I have seen no complaints.
Why would I need the two mic channels? Wouldn't a simple input/output work? What are the advantages in buying a 30$ phantom power (if there is) and 100$, in audio quality I mean, aren't they just feeding the mic?
I have two AKG P150 Small Diaphragm Capacitor mics and they are pretty good. The P 120 is an LDC and unless you have a very quiet, pretty acoustically 'dead' room I would avoid it. Nothing WRONG with the microphone but a dynamic worked very close might be a better bet. Or look for an SDC but get one with a 10 or 20dB attenuator switch (the P150, now 170 has such a switch). SDCs are the Swiss Army Knife of mics, very suitable for recording all manner of acoustic instruments and generally have a neutral character, i.e. they don't add any colouration to the sound. LDCs and especially dynamics tend to do this and you might like the result..might not!
Lastly (for now!) you seem to understand that you need some recording software? Known as a Digital Audio Workstation. Almost all AIs come with something, the Steinberg with a light version of Cubase, an excellent DAW if one of the hardest to learn. But! ALL DAWs demand application but a dedicated evening should get you recording and building simple tracks.
I already have cubase, because I bought a digital guitar pedal from zoom.
My room is quiet, I have isolation with pladur walls from the exterior, but I guess it would pick up the noise from the computer.
So you would recommend a dynamic? Like the Shure SM58, I would still need phantom power?
There are things that a pro like you might notice, but I really wouldn't
. I don't want to buy something expensive that I don't need, that's just my concern. I just want to experiment, and my computer/phone mic is not the way to go.
Would there be a significant difference in audio using the Shure SM58 or the AKG P120/150?
Again thank your the answer.
EDIT: I didn't find the akg p150, but I found the p170 which is an SDC aswell.