Shop4Tech offers the Spacerail Level 2 Steel Ball Roller Coaster Kit, model no. 231-2, for $39.95. Coupon code "NB20" cuts it to $31.96. With free shipping, that's tied with our mention from last week and $3 less than the lowest total price we could find for any Spacerail set sold elsewhere. This kit allows you to construct a "roller coaster" for steel balls, included, to navigate via gravity. Coupon ends November 18.