UK lights

Hello,

Im a first time grower. Nearly killed my plants by not watering them for 10 days while on holiday. They are recovering now and hopefully can make it.

I need lights, can anyone suggest anything?
The plants get an average amount of light already (south facing window), but direct sunlight is so minimal in the UK and its already end june and they still haven't got any strong sunlight.
They are growing taller i feel, with less leaves. It's approx 60cm tall and on it's 5th set of leaves.

What kind of lights would you suggest? I've seen quite a bit of information about different types of lights for different stages, different spectrums and HPs of the lights and different intial costs and electricity/maintenance costs.
Too much information, i need help. I only have 3 small plants- need something that they can vegetate on and flower on. I won't grow in winter so dont need the strongest lights and it's near a window, the space is ventilated enough to not worry about over heating.

Can i get something for like £60?
Does anyone have links they could suggest?


Thanks!
1st timer