There is a Czech company that produces pretty decent two-purpose tires. These are dirt-cheap (at least in Europe) and certainly worth to have a look at:
Mitas Tires North America, Inc. (formerly CGS Tires US, Inc.)
7400 Carmel Executive Park, Suite 100
NC 28226 Charlotte
Market Manager: Neil Rayson
Tel.:+1 704 542 3422
Fax:+1 704 542 3474
neil.rayson@mitas-tires.com
In Germany both tires are less than 40€ (including 19% VAT!)