i wouldn´t recomend you weight gainers at all, they´re full of sugar and too expensive. try making your own mass-building shakes instead.
try this: 0,5l of milk
30g of whey
100g of oats
1 banana, strawberry, whatever you like
put´em in a mixer and there you go ! you can put that stuff in a bottle and cary it to school, work... it´s healthy and much cheaper and really tastes good.
one shake of the above contains: ~52g protein