You can eat as much protein as you want, I go as high as 2 x bodyweight when bulking.
Instead of paying for an expensive weight gainer, you can try adding olive oil (or any other good oils) to your protein shakes. Olive oil is very calorie dense. When I was struggling to gain weight early on, I would drink the following shake before bed each night:
Homemade Gainer Shake
2 cups of milk (preferrably whole milk - remember that calcium is critical in the muscle building process)
4-8 scoops of whey (depending on how thick this makes your shake - more scoops obviously is better if you can keep the shake thin enough to still drink it)
1/4 cup olive oil
sugar to taste if necessary
use a blender to mix, then either chug the shake or whatever you have to do to get it down.
The result is, depending on how much protein you put in it, a shake with over 1000 calories and up to 200 grams of protein. This really made a huge difference for me when I was first trying to gain weight and couldn't physically fit as much food into my body. Eventually your body will adapt to the extra food intake and you will be able to handle eating more, and when that time comes then of course you can cut back on these gainer shakes or replace them entirely with food. But protein shakes are not the devil, whatever you have to do to get enough calories and enough protein.