Ok, about to start a basement finish (DIY). (Well, my husband is.
3200 square feet. Exterior basement walls are superior walls (nailer built into concrete studs) and are almost 9 feet high.
Question is on the interior stud walls.
2 by 4 by 10 foot is $3.38 each here in Michigan
2 by 4 by 7 feet id $1.33
Using 7 footers instead of 10 footers would save us about 50% IF
We build a short 20 inch wall, bottom plate, top plate, 16 oc, etc. Then we nail a top plate to the floor joists above and toe nail in 7 foot stids between the 20 inch wall and the top plate on the ceiling.
If we use 10 foot studs, a 10 foot wide wall costs $37.18.
If we use the 'wall on wall' method with 7 foot studs, the cost would be $19.95 plus extra nails.
(time does not matter, i won't let him do anything else anyway
See any problems with codes or practical problems, electrical will be above 20inches anyway.