A very cheap & easy way for a seat tube bottle is to get 2 hose clamps from Home Depot or Lowes (under $3.00) and just clamp on a bottle cage. My old Raleigh only has one set of braze-on's so I added a 2nd on the seat tube. I can take it off for winter riding and I put electrical tape under the clamp so as not to scratch the paint.
