when you say not good for flower do you just mean big yields? im not expecting a massive grow. wasnt expecting 6 seeds to survive tho lol. and regards to hps aint they expensive to run?
Expense comes down to the power they consume so if you bought a few of the lights you have and they were equal wattage to the HPS it would just cost the same.
But really a 600w HPS is not expensive to run unless you live in an area with a really high price on the kwh. Its very easy to calculate the cost. It gets expensive if you want to light 3 rooms with 4x 1000w Lights but then if you were doing that the cost is relative to the product produced.
When I say they don't do well in flower, its basically because in veg plants can tick along nice with not much light, when you flower they need a lot more light, so this is where people find they struggle, a 135w LED in a 4x4 for example isn't going to flower well so you would end up with tiny buds which don't develop well, don't fill out, don't weigh much and take twice as long to finish.
Don't get me wrong, I'm not one of those guys who shouts buy a HPS at everyone using an LED. I used to use HPS and now I use very high quality LEDs. But they cost a lot of money to make, build or buy ready made, which is why I suggest HPS, its cheap and reliable and performs well and always has.