The cost of the two laptops is 2 x $600 = $<<2*600=1200>>1200.
The cost of the four smartphones is 4 x $400 = $<<4*400=1600>>1600.
Thus, the total cost of all the items is $1200 + $1600 = $<<1200+1600=2800>>2800.
Therefore, Celine gets a change of $3000 - $2800 = $<<3000-2800=200>>200.
#### 200