Any cheap (<100 euro) tools for observing the lines in solar spectrum? I am now reading the book ''The story of Helium and the Birth of Astrophysics''.

I really want to observe the lines (dark or bright) in the solar spectrum.

Any easily available tools for an amateur?
You need a diffraction grating in order to split the sunlight into a spectrum. It turns out even a normal CD or DVD because of the pits that they have to encode data work very well as high resolution diffraction gratings. You could make a simple enclosure with a CD and a slit like this:

http://coolcosmos.ipac.caltech.edu/cosmic_games/spectra/makeGrating.htm

This should allow you to observe the sun's spectrum, although I would also recommend that you be very careful when observing the sun directly. Preferably use a very narrow slit--this will both make it safer and make the absorption lines much clearer.