If you don't currently subscribe to Amazon Music Unlimited, this is basically the best deal of the year. When you get a month of Amazon Music Unlimited ($8 for Prime members, $10 for non-Prime members), you can get an Echo Dot smart speaker thrown in for just $1 extra.
The only catch is that you can't be a current Amazon Music subscriber, and your Amazon Music Unlimited subscription will auto-renew at $8 or $10 per month, depending on whether you're a Prime member. But you can cancel at any point in the first month to avoid that renewal...and still keep Echo Dot, essentially for $1.
Echo Dot + 1 Month Amazon Music Unlimited | $9-$11 | Normally $58 | Current Amazon Music Unlimited members excluded