Hopefully they won't kill this since its been "found" but there is a pattern in figuring out 10% coupon codes. Basically, sign up for their free catalog, which will be mailed to you roughly once a month. Right under the Nashbar.com logo on the upper-right hand corner on the cover it will say something to the effect of Catalog XXX. If you add a W in front of the catalog number, you now have a 10% discount code.

For example, the current catalog number is 223. If you enter W223 in the coupon field at checkout, you will receive 10% off. The catalog numbers seem to be successive so its likely that once W223 stops working, W224 will work and so on.

Enjoy it while it lasts