Yeck!!!!! I used to hate it when folks asked if they could borrow one of my mics. At least back in my bluegrass days we used hot condenser mics and stood way back from them...relative to other genres.
When you consider Open Mics and Karaoke, you are exposing yourself to hundreds of other people's germs, viruses, etc. The ad suggests getting your own mic, and when you can get an SM58 for around $100, that's good advice. There is a cheaper method, though, about $2.00.
Good advice ... we already have an AT 2050. Makes even my voice sound listenable! Don't do the open mics much anymore but used to do them in Nashville.