I did some analysis and found the following low prices for 6" x 20 ft long stainless that I thought I'd share with you (and insulation prices). Note, some is 316Ti and some is 316L stainless. You can go to the sites I listed to see prices for other diameters/lengths.
1) 20 ft of 6-in Everguard Foreverflex (has a forever warranty) in 0.006, 316Ti, and the upper chimney kit, all for $ 397.66 is located here: shipping is free.
http://www.cjshomedecor.com/acatalog/Foreverflex_316Ti_Stainless_Insert_Liner_Kits.html
the insulation kit for this is $258 and is located here:
http://www.cjshomedecor.com/acatalog/Superwrap_Foil_Insulation.html
Total liner kit plus insulation cost: $656 (free shipping)
2) 20 ft of 6-in Rock-Flex (made in USA and has a lifetime transferable warranty) in 0.006 316Ti, and the upper chimney kit, all for $ 385 is located here:
http://chimneylinerinc.com/
the insulation kit for this is $250 and is also located here:
http://chimneylinerinc.com/
Total liner kit plus insulation cost: $635 (edited...they e-mailed me and said free shipping)
3) 20 ft of 6-in 0.006 (lifetime warranty, made in USA), 316L, and the upper chimney kit, all for $ 289 is located here (note: they claim they'll beat any other price on the net if you find a lower one). I didn't see any strap-on insulation kits, only the pour stuff:
Edit note on 31 Jan 2007: called them and shipping adds about $48 to Ohio. Total estimated cost $337
http://chimneydepotsupply.com/chliki.html
4) 20 ft of 6-in 0.012 (double wall, internal wall is smooth, lifetime warranty, made in USA), 316L stainless, and the upper chimney kit, all for $ 399 is located here (note: they claim they'll beat any other price on the net if you find a lower one). I didn't see any strap-on insulation kits, only the pour stuff: Edit note on 31 Jan 2007: called them and shipping adds about $48 to Ohio. Total estimated cost $447
http://chimneydepotsupply.com/2chliki.html