so I bought 24 CFLs... at um 6 bucks a pack of six? 4x$6=$24... clamps lamps: $4x12, $48... splitters (so I could put two bulbs in one lamp: I forget, less than $10 for 12.. total cost ~$82 for ~480 Watts. I haven't seen much in HPS 400w for under $150... (maybe $130 at the lowest?).
Of course there's the quality of light situation... but for the cost CFLs have done great for me... Vegged 12 plants under that 480 (actually I sprouted them under 2x24w CFLs and slowly grew to the 24 for the 480 by the end of veg) and they're pretty nice looking (all other factors considered). But I also have a small cab 3x4x4, any HID would be too hot and intense for those conditions, I think... I got down to 8 plants by flower and switched to LED, with a couple of CFLs for additional... the temp is just right like that. Again, doing great.
Being able to stretch the cost over time was helpful. The fact tat all I bought is reusable and will in fact see a lot of use from me for other thins is also a big bonus.
I've consistently had CFLs outlive HID bulbs and ballasts (due to their higher intensity)... and then you have the actual added running cost (since you need to cool... it's bulb wattage plus watts for the vent fan to cool the bulb...
CFL are definitely , at the very least, a good way to get into growing.
and as you said, the saving they provide can help someone save for their next step.