Walmart offers the Holiday Time Multi-Color LED Dome Lights 1,000-Bulb Set, model no. 78-113B (not pictured), for $49.98. Choose in-store pickup to dodge the $4.97 shipping fee. (Alternatively, pad your order to over $50 to net free shipping.) That's $10 off and the lowest price we could find. It features four 250-bulb strings, great for sending messages.
Amazon offers Prime members the Design Master 6-oz. Crystal Frost Aerosol Spray, model no. DM800, for $4.77 with free shipping. (Non-members can spend $49 or more to qualify for free shipping; otherwise, shipping costs $6.81.) That's the lowest price we could find by $5. It purports to replicate unique patterns of frost crystals on glass.