Hopefully someone with more experience than me will be along shortly to help you.
There are plenty of free plans around for hot smokers if you set to work with Google. Some are as simple as adapted galvanised dustbins and incinerators that you can buy at ironmongers.
I've just made my own cold smoker from some plywood and pine battens for less than �20; there's some piccies of it
on this thread. However, Jen has cold smoked successfully using a standard kettle barbecue and I believe there are other home-made cold smokers which conduct smoke into the chamber from a separate firebox
You might find
Keith Erlandson's book a useful primer.
Happy smoking
.
Gill