Do! I love reading manga. It sucks though that there aren't any at my local library and they cost an average of nine dollars each, which you can read one issue in about an hour. But I still love to read them!
I would check out your local second hand book store. there is one called Half price books or Crown books that seems to be a chain store. they sell mange for 5 to 3$.
Plus going to conventions and buying books at swap meets, or even checking them out from a library is a good idea. Amazon and ebay should also sell second hand manga for the cheap. I would look into everything.
I think it depends on the manga. Some are pointless and a waste of time to read and many of them are fun and have beautiful artwork. It depends.
I do, however, think it's a waste of time to buy manga. I don't understand people who will buy all of a series like Naruto or Bleach or One Piece (any of the really really long ones) when you can read better translations online for free. XD
I like to have the physical copy of my favorites (which includes only Death Note and Vampire Knight for the time being) because I like to draw from them and I also loan them to others. Other than that, I agree. It's a waste of money.