The UVB bulbs are going to be expensive, wherever you get them. You can get them for less at Reptile Depot or LLL Reptile. I'd bet that the fixture part is standard, though, and you can certainly get one first and then take the bulb or a drawing of it to Wally World or Home Depot to find a fixture that will fit. Pet stores really do overcharge on these things.

As for your constant cycle, there are actually light hoods made for reptiles that have a built-in timer and will handle cycling for you. They're not going to be cheap, though.