Stefan,
If you buy a tool kit, make sure the tools are demagnetized. Most come this way already, but ya never know. Belkin makes several kits, differing only in the number of pieces included. A couple of their kits include their wrist strap, which is also available separately for around $3, and is a nice quality one.
Personally, I own and use an anti-static work mat. Not only does it guard against static, but it is a nice surface to lay things like mobos on when you're installing the CPU and RAM. I got mine at MicroCenter - a generic model for like $10. Right next to it was a brand name mat which looked identical, but cost $39. Go figure ...