where can i buy a mimosa pudica (sensitive plant) ??

There are several suppliers listed in the RHS Plant Finder - go to:
http://www.rhs.org.uk/rhsplantfinder/plantfinder.asp
or it might be fun to grow from seed - several suppliers of seed, Thompson and Morgan & Chiltern Seeds to name two.

Seed is easy and economical and postable! try Chiltern Seeds.

hi saw this today 21/2. i sowed seed hat i have had for 12 yrs now. 3 are showing green today :o). they were T&M seeds. they still do them too.

Here is the source that seems to have the highest quality seeds http://www.sensitiveplant.com