Kristine spends $3 + $1 = $<<3+1=4>>4.
Three sets of barrettes cost 3 x $3 = $<<3*3=9>>9.
Crystal spends $9 + $1 = $<<9+1=10>>10.
Therefore, the two girls spend $4 + $10 = $<<4+10=14>>14.
#### 14