Joined: Jan 2009
Posts: 44,171
Likes: 6,396
From: New York, NY, and High Falls, NY, USA
Bikes: 1962 Rudge Sports, 1971 Raleigh Super Course, 1971 Raleigh Pro Track, 1974 Raleigh International, 1975 Viscount Fixie, 1982 McLean, 1996 Lemond (Ti), 2002 Burley Zydeco tandem
100% wool is nice, but if there's at least 15 or 20% nylon (or other), it can be more durable and isn't necessarily less comfy.
If you want to save money, I think a regular old wool sweater, not cycling specific, can be OK.