The black part of the web is a standard 8" web from a party store. The blue is 50 feet of El Wire from glowing stuff (el wire cheap). At more than $1/foot, that's an expensive web! It would require about three times that amount of wire to light up the whole web.
The spider is a prop from Party City, but with the head carved out to hold a pair of 9V batteries to drive the extra bright LEDs in the eyes.