I've started to archive my vinyl collection and use an Artproaudio Phono Plus preamp with a 2015 iMac. For between £70 and £80 you'll get a state of the art preamp which can be powered via its USB output. It will cope with an input from a cassette/tape deck and has switchable RIAA EQ so its just as good for turntables. The other advantage is that it has a variable input gain which you don't get with some high end sound devices (e.g. Apogee).

Rather than Audacity, as everyone seems to recommend, I'm using an application called Vinyl Studio within which you can split your recordings into tracks, clean up scratches and surface noise etc and transfer the results into iTunes, burns CDs etc etc all non-destructively. For around £25, its a steal. I've no complaints about it and still finding things it can do.