...and of course it depends a lot on what you want to record and how.
If you plug a guitar/bass/etc (via a 3.5mm jack adapter) you will not get good results as the mic/line input on your computer is not set up to accept high impedance signals like guitars & basses. Even my fancy audio/MIDI inteface is the same & I had to spend another 20 UK pounds on a direct inject box to get decent recordings of electric instruments.
If you "just" want to record singing, you are faced with either the internal mic on the computer, the quality of which will be OK for spoken word but dire for singing.
Otherwise, you will be looking at either buying a USB mic, which to be honest will severely limit your options when it comes to recording anything else at the same time, or dynamic mic (ideally at least like a Shure SM58) and once again an adapter from XLR to 3.5mm.
Frankly once you decide what you want to do, it would be a better bet to spend a little money on a decent basic recording interface, typically like the focusrite with a single input or a dual input. The latter would at least let you record both your vocals and your electric ukelele at the same time!
It would pay you to check out the free user guide and if you are into visual stuff, the excellent free video tutorials, all available at reaper.fm
Have fun!
P.S. Oops! I forgot to welcome you to the forums!!