Make the top yourself or have a local hardware store or glass/plastic company cut it. You're not going to get a decent light (at least for live plants) with a 40g tank and a top for $130 imo, so if you want live plants i wouldn't factor that into the cost. If you just want a basic light, thatpetplace has 48" lamps in the $60-70 range, but you could probably get cheaper on ebay or a hardware store. The petsmart deal may still be cheaper than the petco $40 tank though, if you don't care about growing plants.