Amazon sells some great 4 ft 4,500 lumen 6500k LED shoplights (brand name is Barrina). I have 6 of these in addition to 6 HO 4ft T5's and 2 2ft 22W LEDs. This is years of culmination however. I started with 3 plants and 2 4ft T5's. I much prefer the LEDs though. I've noticed new growth will literally be touching the diffusers wherever they can (not possible with fluorescents -- too hot). As the technology improves and becomes cheaper, I see more and more options on Amazon than ever before. I still like to search around to see what I can find. In fact, recently I made a lantern with a 17W 6500k LED bulb ($27 on amazon) in the top that I keep one of my favorite mame boxwoods in. It sits on my desk at the office and works off a timer. All of my lights are 6500K because I don't grow any citrus and the flowering trees can flower if they want but I don't actively encourage it. I go for pure growth and small leaves.
Be ready for a fight if you say you're growing bonsai indoors. I can't tell you how many "experts" harp that the trees won't grow inside, that they need dormancy, that they need "wind", that they need "the sweet summer air," that they need "mother earth." Honestly little of it is rooted in science and more often is a result of their aversion to anything different. I grow elms, junipers, maples, boxwood, cypress, ficus, kyoto sport, 3 different redwoods, fukien tea.... to name a few, all with nearly year round growth. And I've been doing it for years. Watch your humidity and possibly invest in a humidifier. God help me it's a stupid hobby......