Rollinbud: I know there are a lot of sources on line. That's where I bought my first T-5 fixture and that turned out to be a mistake. I found one better at my local hydro store and that might be your best source for a couple of reasons. First, your local hydro store can be a great source of general information and buying opportunities for things you'll need in the future. Mine took me under their wing about four years ago and since then realizing that I'm a faithful customer they've turned me on to some sweet deals that floor traffic doesn't usually even know about.
Second, I like to know what I'm getting before I buy it. A lot of online merchandisers are selling us imaginary apples from an empty cart. Unless you've physically seen what you're going to buy up close some where else you can't be positive of what you're getting and there's often a disappointment in what you finally receive compared to the picture you saw on a web site. At least that was my experience and returning something you bought on line is usually a time consuming bitch.
I bought my first fixture on line thinking that I was going to save about twenty bucks compared to what they had in the local hydro stores and I didn't mind waiting the predicted month. But by the time I got it there was no savings. It actually cost more. After paying almost $10 in sales tax, the same as I would in California and almost $20 in shipping and handling, because of the weight, to get it here from Michigan, it actually cost more than across the counter. And the one I bought on line has a crappy reflector. The one I saw and bought at the store is much better quality.
In southern California we have almost as many hydro stores as dispensaries and we have more dispensaries than Starbucks. Competition is usually good for the consumer. I found that I have five hydro stores almost equal distance from my home. They all sell the same brands and models yet the price varied about $20 for the same four tube T-5 fixture 2' long. One store, Discount Hydroponics at Riverside, California really wanted my business. They sold me my second fixture and third fixtures, and when it was all said and done it actually cost less there than the first one I bought on line. And I could see it and compare it on the spot. It has a better reflector and I didn't have to wait three weeks for delivery.
On top of that they invited me to sit in on their free hydroponics classes and for the last couple of years I've learned a lot and gotten a lot of helpful advice. I would encourage you to investigate what you have available locally first. And buy one, not only long enough but wide enough to cover your grow. I didn't and I regret it. All mine are four tubes wide and now I wish I'd bought one six or eight tubes wide to cover my whole tent. I hope this helps. HSA