Joined: Jan 2008
Posts: 23,645
Likes: 1,109
From: Mans of NC & SW UT Desert
Bikes: 86 Katakura Silk, 87 Prologue X2, 88 Cimarron LE, 1975 Sekai 4000 Professional, 73 Paramount, plus more
Count the number of gears in back: six, seven, eight or whatever; and get chain that matches that count. The lower the count, the lower the cost of the chain. Will need a chain tool as well. Sheldon Brown site has good info on chain length.
Good chain tools are not cheap, but can last a really long time. So get a good one. Tools rarely pay for themselves on the first job.