My best mate got a drum kit for Christmas and picked it up really quickly so decided he should start a band. Seeing as I was his best mate he asked me if I'd like to join rather than try to find somebody that could actualy play already. He suggested bass as I wouldn't have to learn to play chords so we could start playing sooner.
Because he was really into Nirvana at the time he gave me a cassette copy of Unplugged in New York to learn and an old acoustic guitar with only the E and A strings on it. Within a week I'd learned the bass parts by ear (pretty accurately to be fair looking back) to about 2/3 of the album and I was hooked.
So that I could be heard against his drum kit, my mate then lent me the money to buy the cheapest bass that was available in that week's Free Ads paper - a Hohner B2a for £70.
I didn't have an amp so I plugged into his Goodmans twin cassette home karaoke machine which was just about audible over the drums with the volume on full but distorted horribly.
My older sister then introduced us to one of her husband's friends who played guitar and sang so I had to get my first bass amp (a Laney Linebacker 30) so that the karaoke machine could be our vocal PA. We were terrible but it was a start and within a year I'd joined the band that I'm with today and have been gigging with for over 23 years!