Does your tank have a brace in the middle? I found a 20" quad t5 that's 72 watts total, for $60, and you would need at least two. If you want high light, you could do four, but replacing at least 8 T5 bulbs every 6-12 months would cost A LOT. LED lights are more expensive up front, but you don't need to replace the bulbs. I found an LED light fixture, a two pack, actually 40" long, and each light has 25 watts, not a lot.. So a total of 50 watts. That would put you at the high end of low, low end of medium. Not the best brand, and it's 10,000k, and plants use more around 6,500k. The LED would work, but not THE BEST.
And having a bowfront tank, you may want to have two fixtures, so that's more cost right there.