My 1987 Jamis Dakar wasn't looking very good at the thrift store, but closer inspection showed Tange Prestige tubing and the 6-speed Deore XT parts group, so I bought it.
You've got to play opportunist because you never know what sort of bike at what sort of price will fall into your lap.
I paid $80 and the paint was in poor shape, but that is a big plus in that it helps prevent theft. I use the bike with it's rack for short errand rides around town, and it seems ideal for that, plus it will handle off-roading.
I discovered the rims were still in like-new condition, so it hadn't been used off road. This meant that the brakes work oh-so-smoothly.