Mt advice on weight gainers is: Try a highly rated one and see how you like it. There's nothing wrong with using a weight gainer to reach your goals, but I wouldn't suggest more than one shake worth a day. If you need more than that, re-evaluate your overall diet.
Now for my spiel on common excuses for not cooking nutritious, calorie dense, great tasting meals. You might not make any of them, but for posterity's sake, here they go.
1. "I don't have enough time" Yes you do. Next.
2. " No really, I don't have enough time." Refer to number 1. If time really is an issue, if you're working 80 hours a week, have a family, children, and run a charity on the side, ok, I get it. You're as busy as the rest of us. Make big batches of awesome food and freeze it. Get a crock pot and make loads of stews and chili and add cheese and sour cream.
3. " I can't cook" Ok. I was a terrible cook at first, but after a couple weeks, I got a lot better. Practice a little, start with easy recipes, follow the book, and it will work out. Plus, its WAY cheaper to eat at home than to hit restaurants all the time.
4. "I'm in college and have no where to cook" Buy a microwave and a 2 burner electric hotplate. This is all you need for some really great meals.
5. " I live at home and my parent's don't support this type of thing" Get a job, buy some food, cook it, and eat it. If they forbid you to do it, either respect them, or get your own place.
6. "Its too expensive" It really isn't. Peanut butter, whole chickens, rice, beans, pork. Look for sales and you can eat like a prince for a price that will fit any budget.
7. " I can't eat that much food" This I have a little sympathy for, but not much. Work at it, and this is finally where the weight gainer comes in. A shake is easier to keep down than 3 pounds of ground beef, a pound of pasta, and a loaf of bread (which incidentally sounds like a nice light snack before supper to me).
Buy wisely, eat to failure, and use supplements strategically and you'll be set to grow.