I agree with HK - I see no problem with prepping for the SAT, and I expect my kids to prep (for SATs in HS, not 7th grade). Prepping boosts scores for most, unless you are like the kid I knew who got a 1600, one time testing, no prep (that is unusual though, even among PG kids).
There can be a difference in admissions at elite schools between the 2100 score and the 2250 score. Also, many merit scholarships are based on SATs (M+V). A score of 1400+ on the SAT or 32+ on the ACT will get you some nice merit. I know one kid that refused to retake the SATs, even though a M+V score just 20 points higher would have secured $8K more a year in scholarships. A little prep, $50 SAT fee and a Saturday morning would have saved his folks $32K.
Prep doesn't need to be fancy and expensive. $100 worth of books (one for CR, one for math, the College Board Blue Book and the ACT Red Book) resulted in a score boost and $20K/year in merit for my eldest.
